JP7500118B2 - Fan blades, engines and structures with anti-icing and de-icing functions - Google Patents

Description

The present invention relates to fan blades, engines, and structures with anti-icing and de-icing functions used, for example, in aircraft.

In recent years, the size of fan blades has increased, fuel efficiency has improved, and development has been carried out to improve impact resistance and flutter resistance in the event of a foreign object entering the engine. However, at the same time, there has been another fundamental issue in that the weight of the fan blades has increased, which has resulted in the engine itself becoming heavier. Furthermore, fan blades have the characteristic that ice accumulates on them for each blade when the aircraft flies at high altitudes in a cold environment. This icing is a complex natural phenomenon that combines the aspects of fluid and heat, and it is an important issue that must be resolved immediately because it reduces the performance of the jet engine during operation and, in the worst case, carries the risk of mechanical damage to the inside of the jet engine due to surges caused by blockage of the flow path and shedding (the phenomenon in which ice that has grown due to icing breaks off).

To solve the issues of improving fuel efficiency and increasing weight, the use of carbon fiber reinforced plastic (CFRP), a composite material with high specific strength, specific elasticity, excellent mechanical properties, and high-performance properties such as weather resistance, is becoming more common for fan blades.

The development of carbon fiber reinforced plastics, a resin-based composite material, began in the 1960s, primarily for military aircraft. Taking advantage of the composite material's characteristics of excellent rigidity and extremely low thermal expansion, it is replacing conventional metal materials in modern aircraft and is also being put to practical use in new aircraft applications. It is noteworthy that the strength and elastic modulus of current composite materials are more than 2.5 times that of steel, and their specific gravity is less than 1/4, indicating the potential for improved mechanical properties and weight reduction. In fact, in recent years, composite materials have been used to make up more than 50% of the aircraft weight in large aircraft such as the Airbus A350 and Boeing 787.

To address the latter issue of icing, aircraft and engines are equipped with anti-icing and de-icing systems. The following technologies have been disclosed as such systems:

Non-patent document 1 discloses a technology that utilizes high-temperature air (bleed air) extracted from the engine compressor.

Non-patent document 2 discloses a technology that uses an electric heater with an attached heating wire or the like.

Non-patent document 3 discloses a technology that utilizes shape changes by blowing air into anti-icing boots (rubber membranes) attached to the leading edges of the main wings and tail, inflating them.

Patent documents 1 and 2 disclose technologies that utilize coatings that are applied in advance to areas prone to icing, baking, or nano-sized structure pin processing.

Patent document 3 discloses technology that utilizes mechanical vibrations such as actuators.

JP 2012-26361 A International Publication No. 2008/087861 US Patent Application Publication No. 2013/032671 JP 2019-108818 A

Japan Society of Aeronautical Technology, "Aeronautical Engineering Lecture 3: Aircraft Systems", p. 163 Japan Society of Aeronautical Engineers, "Aeronautical Engineering Lecture 8 Jet Engine (Structure)", p. 120 Japan Airlines Public Relations Department, "Practical Aviation Dictionary," Asahi Sonorama, pp. 133-144

Regarding technology that utilizes bleed air, when engine power is low, the anti-icing function is reduced, resulting in inconsistent effectiveness, and because engine power is reduced due to the bleed air, fuel consumption also worsens.

As for electric heaters, it is difficult to set up and process the fan on thin components, and this also has aerodynamic effects.

As for anti-icing boots, they require complex mechanical structures inside the wings to operate, as they use bleed air from the engine compressor, and they need to be replaced every two to three years.

Anti-icing coatings and nano-structured pins suffer from instability and lack of durability over time.

Regarding mechanical vibrations from actuators, etc., their complex structure makes them difficult to maintain and increases their weight.

The conventional technologies described above are countermeasures specifically aimed at the problem of icing, and because they are technologies that achieve their functions through configurations and structures that are added (supplemented) to conventional aircraft specifications later, it is clear that the volume and weight will be greater than the basic specifications, the configurations and structures will be more complex, and processing and maintenance will be more difficult, and other impacts will occur.

In view of the above circumstances, the object of the present invention is to provide a fan blade, an engine, and a structure with anti-icing and de-icing functions that have a simple structure and can efficiently perform anti-icing and de-icing.

A fan blade according to one embodiment of the present invention includes:
A fan blade disposed on the intake side of the engine,
A fan blade body made of carbon fiber reinforced plastic;
a pair of first and second current-carrying parts for passing a current through a current-carrying region of the fan blade body by passing a current through carbon fibers contained in the carbon fiber reinforced plastic;
Equipped with
When an electric current is passed between the pair of first and second conductive portions, the amount of heat generated in the conductive region on the first side of the fan blade body is higher than the amount of heat generated in the conductive region on the second side of the fan blade body.

The fan blade according to one embodiment of the present invention utilizes the property that the carbon fibers of carbon fiber reinforced plastic (CFRP) are conductive, and the matrix material, such as epoxy, is insulating, and therefore generates heat when current is passed through it. That is, a pair of first and second current-carrying parts for passing current through the current-carrying area of the fan blade body is provided on the first and second sides of the fan blade body made of CFRP, and by applying a voltage between them to pass current, the fan blade body itself generates heat due to its resistance, thereby performing anti-icing and de-icing. Therefore, anti-icing and de-icing can be performed with a simple structure. In the fan blade of an aircraft jet engine, the amount of ice accretion is large on the leading edge side (first side), and ice tends to hardly occur on the trailing edge side (second side) because supercooled droplets in the air do not collide with it. Therefore, by making the amount of heat generated on the first side of the fan blade body higher than the amount of heat generated on the second side, the first side can be more efficiently de-iced.

The heat generation amount of the current-carrying region on the first side of the fan blade body is higher than the heat generation amount of the current-carrying region on the second side of the fan blade body,
The conductive fiber density on a first side, which is the ratio of carbon fibers conducted to the first conductive portion relative to the span-wise length of the first conductive portion, may be higher than the conductive fiber density on a second side, which is the ratio of carbon fibers conducted to the second conductive portion relative to the span-wise length of the second conductive portion.

The fan blade body includes a plurality of laminated layers, and the orientation of the carbon fibers included in the plurality of layers is different.
By connecting one or more layers selected from the plurality of layers to the first current conducting portion and the second current conducting portion, the conductive fiber density on the first side may be higher than the conductive fiber density on the second side.

The orientation of the carbon fibers varies depending on the required specifications and properties. By selecting one or more layers with different carbon fiber orientations and connecting them to the first and second conductive parts, it is possible to achieve a difference in conductive fiber density.

The one or more layers connected to the first current conducting portion and the second current conducting portion include
a first layer comprising carbon fibers oriented in a first direction that is positively inclined with respect to both the span direction and the chord direction, and/or a second layer comprising carbon fibers oriented in a second direction that is negatively inclined with respect to both the span direction and the chord direction.

By selecting one or more layers with different carbon fiber orientations and connecting them to the first and second conductive parts, it is possible to achieve a difference in conductive fiber density.

The length of the second conductive portion in the span direction may be longer than the length of the first conductive portion in the span direction.

Focusing on the carbon fibers that are conductive to both the first and second current-carrying parts (i.e., the carbon fibers included in the current-carrying region), the number of carbon fibers that are conductive to the first current-carrying part is the same as the number of carbon fibers that are conductive to the second current-carrying part. Therefore, when the same number of carbon fibers are conductive to the short first current-carrying part and the long second current-carrying part, the conductive fiber density on the first side, which is the ratio of the carbon fibers that are conductive to the first current-carrying part to the span-direction length (short) of the first current-carrying part, is higher than the conductive fiber density on the second side, which is the ratio of the carbon fibers that are conductive to the second current-carrying part to the span-direction length (long) of the second current-carrying part. Since the conductive fiber density on the first side is higher than the conductive fiber density on the second side, the heat generation amount on the first side of the fan blade body is higher than the heat generation amount on the second side. The same number of carbon fibers that are conductive on the first side are present in an area narrower than that on the second side. Therefore, the temperature on the first side is higher than that on the second side due to the heat generation of the carbon fibers themselves.

The fan blade body includes a plurality of laminated layers.
a layer on a pressure surface side selected from the plurality of layers is connected to the first current conducting portion and the second current conducting portion,
When a current is passed between the pair of first and second current-carrying portions, an amount of heat generated on a pressure surface side of the fan blade main body may be greater than an amount of heat generated on a suction surface side of the fan blade main body.

When ice accumulates on the fan blades of an aircraft jet engine, the ice accumulates mostly on the pressure side of the fan blade. For this reason, it is desirable to actively heat the pressure side where the amount of ice is large. As described above, when a voltage is applied to the fan blade body between the first current-carrying part and the second current-carrying part, a current flows, and the fan blade body itself generates heat due to the resistance. For this reason, by making the heat generation amount on the pressure side of the fan blade body higher than the heat generation amount on the negative pressure side of the fan blade body, the pressure side can be more efficiently de-iced. By selecting a layer close to the pressure side and applying current, the heat generation area and heat generation temperature can be secured with the minimum applied power, and the heat generation temperatures of the pressure side and negative pressure side of the fan blade can be set. Specifically, the temperature of the pressure side where the amount of ice accumulates is high, and the temperature of the negative pressure side where the amount of ice accumulates is low. This configuration can also function advantageously in the hollow structure that accompanies the weight reduction of fan blades in recent years.

a first-side conductive adhesive and a second-side conductive adhesive for connecting the fan blade body to the first current-carrying portion and the second current-carrying portion,
The heat generation amount of the current-carrying region on the first side of the fan blade body is higher than the heat generation amount of the current-carrying region on the second side of the fan blade body,
The method may include having a resistance value of the first side conductive adhesive higher than a resistance value of the second side conductive adhesive.

The conductive adhesive is used to form a current path between selected carbon fibers, and the resistance component of the conductive adhesive is selected in a ratio that is centered around the area where ice accumulates on the fan blade, providing superior heat generation and anti-icing effects.

The fan blade body includes a plurality of laminated layers.
The first-side conductive adhesive and the second-side conductive adhesive may connect one or more layers selected from the plurality of layers to the first current-carrying portion and the second current-carrying portion.

By bonding the electrode and the fan blade body with a conductive adhesive, the adhesion with the carbon fiber and the contact area are increased, preventing localized temperature rise and poor conductivity at the attachment points between the electrode and the fan blade body and reducing power consumption. This makes it possible to achieve an effective temperature rise even with a low voltage.

a resistance value of the first side conductive adhesive on a pressure surface side of the fan blade body is higher than a resistance value of the first side conductive adhesive on a suction surface side of the fan blade body,
The resistance value of the second side conductive adhesive on the positive pressure surface side may be lower than the resistance value of the second side conductive adhesive on the negative pressure surface side.

When ice forms on the fan blades of aircraft jet engines, in addition to the leading edge and hub, most ice accumulates on the pressure side of the fan blade. For this reason, it is desirable to actively heat the pressure side, where the amount of ice is large. As described above, when a voltage is applied to the fan blade body between the first and second current-carrying parts, a current flows, and the fan blade body itself generates heat due to the resistance. For this reason, by changing the way the conductive adhesive is applied, more current is allowed to flow to the layer closer to the pressure side, and conversely, less current is allowed to flow to the layer closer to the negative pressure side. This increases the amount of heat generated on the pressure side, making it possible to more efficiently de-ice the first side.

the first side is a leading edge side of the fan blade body;
The second side may be a trailing side of the fan blade body.

In the fan blades of aircraft jet engines, the amount of ice that accumulates is large on the leading edge side (first side), while the trailing edge side (second side) tends to have almost no ice accumulation because it is not hit by supercooled liquid droplets in the air. For this reason, by making the heat generation amount of the first side of the fan blade body higher than that of the second side, it is possible to more efficiently de-ice the first side.

An engine according to one embodiment of the present invention includes:
A rotation axis;
A fan disk provided on the intake side of the rotating shaft;
A fan blade according to any one of the embodiments of the present invention, which is detachably attached to the fan disk;
a pair of connection terminals provided on the fan disk side and the fan blade side for each of the first current-carrying portion and the second current-carrying portion, the connection terminals being electrically connected to each other when the fan blade is attached to the fan disk, for conducting electricity between a power source on the fan disk side and the first current-carrying portion and the second current-carrying portion;
Equipped with:

A structure with anti-icing and de-icing functions according to one embodiment of the present invention includes:
A plate-shaped member made of carbon fiber reinforced plastic and having an ice formation region due to a gas flow;
a pair of first and second current-carrying parts provided on a first side and a second side of the plate-shaped member, respectively, to include the ice-accretion region, for causing a current to flow through the carbon fibers contained in the carbon fiber reinforced plastic to cause a current to flow through the current-carrying region of the plate-shaped member;
Equipped with
The amount of heat generated by the current-carrying region on the first side of the plate-shaped member is greater than the amount of heat generated by the current-carrying region on the second side.

According to the present invention, anti-icing and de-icing can be performed efficiently with a simple structure.

Note that the effects described here are not necessarily limited to those described herein and may be any of the effects described in this disclosure.

1 is a schematic diagram showing a configuration of a jet engine according to one embodiment of the present invention. FIG. 2 is a side view showing the basic configuration of a single fan blade shown in FIG. 1 . 1 is a schematic diagram showing a configuration of a fan blade according to an embodiment of the present invention. 4 shows a modification of the fan blade shown in FIG. 3 . 1 is a graph showing test results. FIG. 2 is a perspective view showing a state in which fan blades are attached to a fan disk. FIG. 4 is a diagram for explaining the configuration of wiring for supplying power to a fan blade according to an embodiment of the present invention. FIG. 4 is a diagram for explaining a configuration of power supply to a fan blade according to an embodiment of the present invention. FIG. 11 is a diagram for explaining another configuration of power supply to the fan blade according to the embodiment of the present invention. FIG. 2 is an exploded view showing a schematic of laminated prepregs constituting a fan blade body. The cross section of the laminated prepreg specimen used in the experiment is shown diagrammatically. 1 shows a laminated prepreg specimen used in the experiment. FIG. 1 is a schematic diagram for explaining the conductive fiber density used in the experiment. The types 1 and 2 test specimens used in the experiment are shown. The experimental icing wind tunnel is shown. 13 is a photograph showing the results of an anti-icing test. 13 is a photograph showing the results of an anti-icing test. 1 is a graph showing anti-icing test results. 1 is a graph showing anti-icing test results. This is a thermograph showing the results of a windless heat generation test. 1 is a graph showing the results of a windless heat generation test. Another test specimen used in the experiment is shown diagrammatically. 1 is a thermograph showing the test results. 1 is a graph showing test results. Photographs showing test results. Photographs showing test results. Photographs showing test results. Photographs showing test results. 1 is a graph showing test results. 1 is a graph showing test results. 1 is a thermograph showing the test results. A specific example of layer selection used in the experiment is given below. 1 is a thermograph showing the results of a layer selection ventilation temperature confirmation test. 13 is a graph showing the results of a layer selection ventilation temperature confirmation test. 13 is a graph showing the results of a layer selection ventilation temperature confirmation test. Photographs showing test results. Photographs showing test results. 1 is a graph showing test results. 1 is a graph showing test results. 1 is a graph showing test results. 1 is a graph showing test results.

Below, an embodiment of the present invention is described with reference to the drawings.

I. Overview

1. Jet engine structure

Figure 1 is a schematic diagram showing the configuration of a jet engine for one embodiment of the present invention.

Jet engine 1 has a low pressure shaft 2 and a high pressure shaft 3 disposed at the center as rotating shafts.
A spinner 5, a fan disk 6, a low-pressure compressor 9 and a low-pressure turbine 15 are attached to the low-pressure shaft 2 from the intake port 4 side, and a plurality of fan blades 8 are attached to the outer periphery of the fan disk 6 via a dovetail 7.

Downstream of the fan blades 8 are arranged a low-pressure compressor 9, a high-pressure compressor 11, a combustor 13, a high-pressure turbine 14, a low-pressure turbine 15, struts 16, and a core nozzle 17, and in a separate flow passage between the outer periphery of these and the engine nacelle 18, a fan exit guide vane 10 and a bypass nozzle 12 are arranged.
A high-pressure compressor 11 and a high-pressure turbine 14 are attached to the high-pressure shaft 3 .

In a jet engine 1 configured in this way, ice forms on the spinner 5 near the intake 4 and on the fan blades 8 due to supercooled water droplets. This ice formation causes problems such as a decrease in aerodynamic performance due to deformation and mechanical damage due to detached ice blocks. The fan blade 8 shown below solves this problem.

2. Fan blade structure (overview)

Figure 2 is a side view showing the basic configuration of a single fan blade shown in Figure 1. Figure 3 is a schematic diagram showing the configuration of a fan blade according to one embodiment of the present invention.

The fan blade 8 is disposed on the intake port 4 side of the engine. The fan blade 8 has a fan blade body 21, a sheath 22 disposed on the leading edge 24 side (first side) of the fan blade body 21, and a guard 23 disposed on the trailing edge 25 side (second side) of the fan blade body 21.

The fan blade body 21 is made of carbon fiber reinforced plastic (CFRP) and is typically a plate-shaped molded product. CFRP is made by laminating prepregs made of carbon fibers as reinforcing fibers and epoxy resin as a matrix, with the carbon fibers oriented quasi-isotropically.

The sheath 22 is made of a rigid conductive metal, and covers the area on the leading edge 24 side of the fan blade body 21, extending from the hub side 26, which is its base, to the tip side 27, which is its tip.
The guard 23 is also made of a rigid conductive metal, and covers the area on the trailing edge 25 side of the fan blade body 21, extending from the hub side 26 to the tip side 27.

The sheath 22 and guard 23 are originally components to respond to bird strikes. In the fan blade 8 according to this embodiment, the sheath 22 and guard 23 are separated so as not to come into contact with each other, and the two are electrically insulated.

3, the fan blade 8 according to this embodiment has a pair of leading edge side current-carrying parts 31 (first current-carrying part) and trailing edge side current-carrying parts 32 (second current-carrying part) provided on the leading edge 24 side and trailing edge side current-carrying parts 25 side of the heating area 36 of the fan blade body 21, for passing a current through the carbon fibers contained in the CFRP to pass a current through the current-carrying area of the fan blade body 21. Note that the leading edge side current-carrying parts 31 and trailing edge side current-carrying parts 32 shown in the figures are schematic representations of their approximate positions, and the shapes of the leading edge side current-carrying parts 31 and trailing edge side current-carrying parts 32 are actually different (described later).

Here, in the fan blade 8 of an aircraft jet engine 1, the hub side 26 of the leading edge 24 has a slow rotational speed and thus tends to have the greatest amount of ice accretion, while the tip side 27 has a fast rotational speed and ice tends to peel off easily due to centrifugal force, etc., making it difficult for ice to accumulate. For this reason, the heating area 36 is typically located on the leading edge 24 side and close to the hub side 26. Anti-icing and de-icing measures in this heating area 36 are important.

The leading edge side conductive section 31 and the trailing edge side conductive section 32 are arranged on the leading edge 24 side and the trailing edge 25 side of the heating area 36, so as to be sandwiched between the surface of the fan blade body 21 and the back surface of the sheath 22, and between the surface of the fan blade body 21 and the back surface of the guard 23, respectively.

The leading edge side conductive part 31 and the trailing edge side conductive part 32 are formed by removing the insulating coating from the tip of the insulating coated electric wire 33, 34, respectively, and are bonded between the surface of the fan blade body 21 and the back surface of the sheath 22, and between the surface of the fan blade body 21 and the back surface of the guard 23, using a conductive adhesive paste (not shown). Here, the fan blade body 21 has carbon fiber exposed parts where the carbon fibers contained in the carbon fiber reinforced plastic are exposed at each position corresponding to the leading edge side conductive part 31 and the trailing edge side conductive part 32. The carbon fiber exposed parts are formed, for example, by scraping off the insulating epoxy resin at the corresponding part to expose the conductive carbon fibers. By further using a conductive adhesive there, it becomes possible to efficiently pass a current through the carbon fibers. This shows that it is possible to form a current path made of conductive carbon fibers based on the material composition of the fan blade body 21 and to generate resistance heating.

A negative voltage, for example, is applied to the leading-edge-side current-carrying portion 31 from a power source 35 via an insulated electric wire 33, and a positive voltage, for example, is applied to the trailing-edge-side current-carrying portion 32 from a power source 35 via an insulated electric wire 34. When a voltage is applied to the current-carrying region of the fan blade body 21 between the leading-edge-side current-carrying portion 31 and the trailing-edge-side current-carrying portion 32, a current flows and the fan blade body 21 itself generates heat due to its resistance. The region heated by the heat generation includes the heating region 36, or the heating region 36 includes a region heated by the heat generation.
A configuration may be adopted in which a positive voltage is applied to the leading edge side current-carrying portion 31 and a negative voltage is applied to the trailing edge side current-carrying portion 32 .

In the fan blade 8 according to this embodiment, the fan blade body 21 is made of CFRP and is conductive, so that the property of generating heat when electric current is passed through it is utilized. That is, a pair of leading edge side electric current parts 31 and trailing edge side electric current parts 32 are provided on the leading edge 24 side and trailing edge 25 side of the fan blade body 21 made of CFRP to pass electric current through the carbon fibers contained in the CFRP to pass electric current through the electric current area of the fan blade body 21, and a voltage is applied between them from a power source 35 to pass electric current through the electric current area, thereby heating the fan blade body 21 and performing anti-icing or de-icing of the heated area 36. At that time, there is heat generated by the CFRP itself (fan blade body 21), and the heat flows and spreads through the CFRP (fan blade body 21), and some of the heat is transmitted as heat conduction to the sheath 22 and guard 23 parts, and each heat acts as anti-icing or de-icing. As a result, anti-icing or de-icing of the heated area 36 is performed.

The heating area 36 where anti-icing or de-icing is performed by such heating can be adjusted by changing the positions at which the pair of leading edge side current-carrying parts 31 and trailing edge side current-carrying parts 32 are attached. That is, insulated electric wires 33, 34 are laid between the sheath 22 and guard 23 and the fan blade body 21, and the contact (electrode) positions between the electrodes at the tips of the insulated electric wires 33, 34 and the fan blade body 21 are adjusted to match the area to be heated.

For example, when performing anti-icing or de-icing on the hub side 26 of the leading edge 24 side, the explanation of Figure 4 shows that when a current path is formed between the carbon fibers of the selected layers via the electrodes, the positions of the electrodes (first current-carrying portion 31 and second current-carrying portion 32) on the leading edge 24 side and the trailing edge 25 side are set closer to the hub side 26. In this way, anti-icing or de-icing on the hub side 26 of the leading edge 24 side can be efficiently performed.

The leading edge conductive part 31 and the trailing edge conductive part 32 are electrodes formed by removing the insulating coating at the tip of the insulating coated electric wire 33, 34, respectively, and are attached to the target part via a conductive adhesive (not shown), so that current can easily flow. Unlike electrodes attached with, for example, copper tape, the conductive adhesive has a conductive material that penetrates into the fine unevenness of the processed surface, which increases the conductive area, resulting in a smaller resistance and making it easier for current to flow, preventing local temperature increases and poor conduction, and reducing power consumption. It has been confirmed that when the electrode is attached with copper tape without using a conductive adhesive, it hardly heats up even with the same voltage. In particular, when considering Joule heat, the current has a square effect, so it is important to make it possible to flow current with the same applied voltage. Therefore, it is considered that the effect of bonding the electrode and the fan blade body 21, etc. with a conductive adhesive is great.

In addition, in the fan blade 8 of this embodiment, the heat generation temperature and heat generation rate of the heating area 36 can be adjusted by changing the magnitude of the voltage or current supplied to the fan blade body 21 through the insulated electric wires 33, 34.

3. Attaching the fan blades to the fan disk and supplying power

Figure 6 is an oblique view showing the state in which the fan blades 8 are attached to the fan disk 6, Figure 7 is a diagram for explaining the wiring configuration for supplying power to the fan blades 8, and Figure 8 is a diagram for explaining the configuration of the power supply to the fan blades 8.

As shown in Figure 6, the fan disk 6 has an engagement groove 41 into which the dovetail 7 attached to the fan blade 8 is engaged. There is a gap between the end face of the dovetail 7 and the bottom of the engagement groove 41.

By inserting the dovetail 7 into the engagement groove 41 from the leading edge 24 side (see the arrow in Figure 8) and sliding the fan blade 8 towards the trailing edge 25 side, the dovetail 7 engages with the engagement groove 41 and the fan blade 8 is attached to the fan disk 6.
As shown in FIG. 7 , the dovetail 7 is attached to the hub side 26 of the fan blade 8 via a platform 43 and a shank 42 .

Connection terminals 46, 49 are attached to the end face of the dovetail 7 on the leading edge 24 side and the trailing edge 25 side via insulating sheets 46a, 49a, respectively. The connection terminal 46 is connected to the leading edge side current-carrying part 31 on the leading edge 24 side via an insulated electric wire 33. The insulated electric wire 33 is wired to the leading edge 24 side of the platform 43 and the shank 42. The connection terminal 49 is connected to the trailing edge side current-carrying part 32 on the trailing edge 25 side via an insulated electric wire 34. The insulated electric wire 34 is wired to the platform 43 and the trailing edge 25 side of the shank 42.

As shown in Figure 8, V-shaped contact fittings (connection terminals) 51, 52 are provided on the bottom surface of the engagement groove 41 of the fan disk 6 at positions corresponding to the connection terminals 46, 49 via insulating sheets 51a, 52a, respectively.

When the dovetail 7 is engaged in the engagement groove 41 and the fan blade 8 is attached to the fan disk 6, the connection terminals 46, 49 contact and press the V-shaped contact fittings 51, 52, respectively. As a result, the connection terminals 46, 49 and the V-shaped contact fittings 51, 52 come into elastic contact with the bottom of the engagement groove 41 and the end face of the dovetail 7, respectively.

The spinner 5 contains a battery 53 that serves as a power source, and the battery 53 and the V-shaped contact fittings 51, 52 are connected via insulated electric wires 45, 48 that pass through the fan disk 6 and the spinner 5, respectively. This provides power for heating to the fan blade body 21. By adopting such a configuration, the configuration for power supply can be simplified.

Figure 9 is a diagram illustrating another configuration for power supply to fan blade 8.

In this configuration, power for heating the fan blade body 21 is supplied from an external, existing power supply system 62. In this configuration, a slip ring 61 is attached to the low-pressure shaft 2, which is the rotating shaft, and power for heating the fan blade body 21 is supplied from the existing power supply system 62 via the slip ring 61. This makes it possible to supply power from an external source.

II. Fan blade

1. Fan blade structure (details)

Figure 10 is an exploded view showing a schematic of the laminated prepregs that make up the fan blade body.

The fan blade body 21 is an example of a laminate of multiple (n layers) 211, 212, 213, 214, ... 21n. Each layer 211, 212, 213, 214, ... 21n is a prepreg that uses, for example, carbon fiber as the reinforcing fiber and epoxy resin as the matrix. Each layer 211, 212, 213, 214, ... 21n may be the same prepreg.

The orientation of the carbon fibers contained in the multiple (n layers) layers 211, 212, 213, 214, ... 21n is different. When the span direction (longitudinal direction) of the fan blade 8 is 0° and the chord direction (short direction) is 90°, the orientation of the carbon fibers contained in layer 214 is 0°, and the orientation of the carbon fibers contained in layer 211 is 90°. Layer 212 contains carbon fibers oriented in a first direction (in this example, +45°) that is positively inclined with respect to both the span direction and the chord direction. Layer 213 contains carbon fibers oriented in a second direction (in this example, -45°) that is negatively inclined with respect to both the span direction and the chord direction. The other layers 21n have a configuration in which a pseudo-isotropic configuration in which carbon fibers are arranged with an orientation direction of 90°, ±45°, 0°, or other angles is repeatedly stacked multiple times.

Even if the multiple layers 211, 212, 213, 214, ... 21n are made of the same prepreg, the strength and rigidity will be different if the fiber orientation angle of each layer 211, 212, 213, 214, ... 21n is different. Utilizing this property, a pseudo-isotropic laminated structure is used in which the prepreg with carbon fibers oriented in one direction is oriented according to the lamination in order to obtain a certain level of mechanical mechanical properties in the circumferential direction. Specifically, the fan blade is laminated multiple times with the carbon fiber orientation direction of 90°, ±45°, and 0° relative to the span direction (longitudinal direction) repeated to obtain the desired mechanical properties. The figure shows an example of pseudo-isotropy, but it does not have to be pseudo-isotropic.

As described above, in the fan blade 8 of the jet engine 1 of an aircraft, the hub side 26 of the leading edge 24 has a slow rotation speed, so the amount of ice accretion is the largest, while the tip side 27 of the trailing edge 25 has a fast rotation speed, so ice is easily peeled off by centrifugal force, etc., so that ice does not easily accumulate. Also, as described above, when a voltage is applied to the electric conduction area of the fan blade body 21 between the leading edge side electric current 31 and the trailing edge side electric current 32, a current flows, and the fan blade body 21 itself generates heat due to the resistance. When a current is passed between the pair of leading edge side electric current 31 and trailing edge side electric current 32, the amount of heat generated on the leading edge 24 side of the fan blade body 21 is made higher than the amount of heat generated on the trailing edge 25 side, thereby increasing the amount of heat generated on the leading edge 24 side (more specifically, the hub side 26) of the fan blade body 21, and the leading edge 24 side (more specifically, the hub side 26) is more efficiently deiced. Furthermore, since the fan blades 8 of the jet engine 1 tend to concentrate ice on the hub side 26 due to the rotation of the fan blades 8 regardless of the size of the fan blades 8 (regardless of the size of the engine), the means described in this embodiment can provide an effective anti-icing effect.

Therefore, in this embodiment, when current flows between the pair of leading-edge-side conductive portions 31 and trailing-edge-side conductive portions 32, in order to make the heat generation amount on the leading edge 24 side of the fan blade body 21 higher than the heat generation amount on the trailing edge 25 side, the conductive fiber density on the leading edge 24 side of the fan blade body 21 is made higher than the conductive fiber density on the trailing edge 25 side. Specifically, by making the ratio of carbon fibers conducted to the leading-edge-side conductive portion 31 relative to the spanwise length of the leading-edge-side conductive portion 31 higher than the ratio of carbon fibers conducted to the trailing-edge-side conductive portion 32 relative to the spanwise length of the trailing-edge-side conductive portion 32, the conductive fiber density on the leading edge 24 side becomes higher than the conductive fiber density on the trailing edge 25 side.

In order to realize the difference in the conductive fiber density, not only one or more layers 211 in which the carbon fiber is oriented at 90°, but also one or more layers 212 in which the carbon fiber is oriented at +45° and one or more layers 213 in which the carbon fiber is oriented at -45° are connected to the leading edge side conductive part 31 and the trailing edge side conductive part 32. The length in the span direction of the trailing edge side conductive part 32 is made longer than the length in the span direction of the leading edge side conductive part 31. On the other hand, when focusing on the carbon fibers that are conductive to both the leading edge side conductive part 31 and the trailing edge side conductive part 32 (i.e., the carbon fibers included in the conductive region), the number of carbon fibers that are conductive to the leading edge side conductive part 31 is the same as the number of carbon fibers that are conductive to the trailing edge side conductive part 32. For this reason, when the same number of carbon fibers are conducted to the short leading-edge-side current-carrying portion 31 and the long trailing-edge-side current-carrying portion 32, the conductive fiber density on the leading edge 24 side, which is the ratio of carbon fibers conducted to the leading-edge-side current-carrying portion 31 to the span-direction length (short) of the leading-edge-side current-carrying portion 31, is higher than the conductive fiber density on the trailing edge 25 side, which is the ratio of carbon fibers conducted to the trailing-edge-side current-carrying portion 32 to the span-direction length (long) of the trailing-edge-side current-carrying portion 32. Since the conductive fiber density on the leading edge 24 side is higher than the conductive fiber density on the trailing edge 25 side, when a current is passed between the pair of leading-edge-side current-carrying portions 31 and trailing-edge-side current-carrying portions 32, the amount of heat generated on the leading edge 24 side of the fan blade main body 21 is made higher than the amount of heat generated on the trailing edge 25 side, and the temperature on the leading edge 24 side of the fan blade main body rises. The same number of conductive carbon fibers are present on the leading edge 24 side in an area narrower than the trailing edge 25 side. Therefore, the temperature on the leading edge 24 side is higher than that on the trailing edge 25 side due to heat generated by the carbon fiber itself.

2. Test specimen

Figure 11 shows a schematic cross-section of the laminated prepreg specimen used in the experiment.

Prepare a laminated prepreg specimen. In this example, layers 211, 212, 213, 214 with carbon fiber orientations of 90°, +45°, -45°, and 0° are laminated symmetrically into 24 layers. This is merely an example, and layers with orientations of +30° to +60° may be provided. For example, layers with orientations of -30° to -60° may be provided. For example, layers with orientations of 90°, +60°, +30°, -30°, -60°, and 0° may be provided. They may be laminated quasi-isotropically, or the proportion of layers with orientations of 90° may be higher than layers with orientations of other angles. In the laminated state, both ends of the leading edge 24 side and the trailing edge 25 side of the multiple layers 211, 212, 213, 214...21n are exposed in layers. Each of the two end faces is, for example, a knife-edge shape consisting of two angled planes, rather than a single plane. The thickness of each of the layers 211, 212, 213, 214, . . . 21n is, for example, 0.19 mm.

The first direction is +30° to +60° and the second direction is -30° to -60° (i.e., an acute angle), so that the spanwise length of the leading edge side conductive part 31 and the trailing edge side conductive part 32 can be made relatively short. This makes it possible to increase the resistivity due to the narrow application area of the conductive adhesive, thereby increasing the amount of heating due to resistance.

Figure 12 shows the laminated prepreg specimens used in the experiments.

In the laminated state, both ends of the leading edge 24 side and the trailing edge 25 side of the multiple layers 211, 212, 213, 214, ... 21n in the cord direction are exposed in a layered manner. Therefore, one or more layers selected from the multiple layers 211, 212, 213, 214, ... 21n can be connected to the leading edge side current conducting portion 31 and the trailing edge side current conducting portion 32 via a conductive adhesive. One layer 21n may be connected to the leading edge side current conducting portion 31 and the trailing edge side current conducting portion 32, a selected portion of the layers 21n may be connected to the leading edge side current conducting portion 31 and the trailing edge side current conducting portion 32, or all of the layers 21n may be connected to the leading edge side current conducting portion 31 and the trailing edge side current conducting portion 32. When applying a conductive adhesive to one or more selected layers 21n rather than all layers 21n, an anisotropic conductive film material or an insulating material (e.g., masking tape in the test) used in high-density mounting of electronic components may be used.

Figure 13 is a schematic diagram to explain the conductive fiber density used in the experiment.

Type 2 is the present embodiment, in which one or more layers 211 with carbon fiber orientation of 90°, one or more layers 212 with carbon fiber orientation of +45°, and one or more layers 213 with carbon fiber orientation of -45° are connected to the leading edge side conductive portion 31 and the trailing edge side conductive portion 32. Specifically, conductive adhesive is applied to all layers in FIG. 11, and all layers are connected to the leading edge side conductive portion 31 and the trailing edge side conductive portion 32. The spanwise length 31L of the trailing edge side conductive portion 32 is longer than the spanwise length 31L of the leading edge side conductive portion 31. On the other hand, when focusing on the carbon fibers that are conductive to both the leading edge side conductive portion 31 and the trailing edge side conductive portion 32 (i.e., the carbon fibers included in the conductive region), the number of carbon fibers that are conductive to the leading edge side conductive portion 31 is the same as the number of carbon fibers that are conductive to the trailing edge side conductive portion 32. Therefore, when the same number of carbon fibers are conducted to the short leading edge side conductive portion 31 and the long trailing edge side conductive portion 32, the ratio of the carbon fibers conducted to the leading edge side conductive portion 31 with respect to the spanwise length 31L (short) of the leading edge side conductive portion 31 is higher than the ratio of the carbon fibers conducted to the trailing edge side conductive portion 32 with respect to the spanwise length 32L (long) of the trailing edge side conductive portion 32. As a result, the conductive fiber density on the leading edge 24 side (the area inside the ellipse in the figure) is higher than the conductive fiber density on the trailing edge 25 side. Since the conductive fiber density on the leading edge 24 side is higher than the conductive fiber density on the trailing edge 25 side, the heat generation amount on the leading edge 24 side of the fan blade main body 21 is made higher than the heat generation amount on the trailing edge 25 side, and the temperature on the leading edge 24 side of the fan blade main body increases. The same number of carbon fibers are conducted on the leading edge 24 side in a narrower area than on the trailing edge 25 side. Therefore, the temperature on the leading edge 24 side is higher than that on the trailing edge 25 side due to the heat generation of the carbon fibers themselves.

Type 1 is a comparative example, in which one or more layers 211 with carbon fiber orientation of 90° are connected to the leading edge side conductive portion 31A and the trailing edge side conductive portion 32A. Specifically, the conductive adhesive is applied only to the two layers (90° orientation) in the center of the thickness direction (center of symmetry) in FIG. 11, and only the two layers (90° orientation) in the center of the thickness direction are connected to the leading edge side conductive portion 31 and the trailing edge side conductive portion 32. Focusing on the carbon fibers (i.e., carbon fibers included in the conductive region) that are conductive to both the leading edge side conductive portion 31A and the trailing edge side conductive portion 32A, the number of carbon fibers that are conductive to the leading edge side conductive portion 31A is the same as the number of carbon fibers that are conductive to the trailing edge side conductive portion 32A. Therefore, the conductive fiber density on the leading edge 24 side is the same as the conductive fiber density on the trailing edge 25 side.

Figure 14 shows the Type 1 and Type 2 specimens used in the experiment.

In FIG. 14, the area surrounded by lines is the area where fiber heating occurs due to conduction, and represents the area to be evaluated as an area when calculating the anti-icing effect. Prepare the above type 1 and type 2 specimens. Both type 1 and type 2 specimens are CFRP laminates with a span direction of 187 mm, a chord direction of 58.6 mm, and a thickness direction of 4.6 mm. The type 1 specimen has a leading edge side conductive part 31A (span direction length 30 mm) and a trailing edge side conductive part 32A (span direction length 30 mm) at the mid-span position, and electricity is conducted between the leading edge side conductive part 31A and the trailing edge side conductive part 32A. The type 2 specimen has a leading edge side conductive part 31 (span direction length 60 mm) and a trailing edge side conductive part 32 (span direction length 100 mm) at the mid-span position, and electricity is conducted in the conductive area between the leading edge side conductive part 31 and the trailing edge side conductive part 32. The leading edge side conductive portion 31A and the trailing edge side conductive portion 32A are conductive adhesives. The size of the heating area is different between Type 1 and Type 2. The area surrounded by the straight lines in the figure is the conductive area between the leading edge side conductive portion 31A and the trailing edge side conductive portion 32A, and is also the heating area and the evaluation area.

3. Test result 1

Figure 15 shows the experimental icing wind tunnel setup.

The icing wind tunnel device 100 has a wind tunnel 110, a droplet catcher 106, a camera (not shown), and a refrigeration room 107 that houses them. The wind tunnel 110 includes, from upstream to downstream, a blower 101, a strainer grid 102, a spray tunnel 103, a contraction 104, and an air outlet 105, which is a test section. The spray tunnel 103 has multiple spray nozzles 108 built in. The camera (not shown) photographs the air outlet 105, which is a test section. The camera (not shown) includes at least a thermal camera, and may further include a camera that takes photographs. The droplet catcher 106 is installed downstream of the air outlet 105.

The specifications of the icing wind tunnel device 100 are as follows: Maximum flow speed: 50 m/s. Temperature: -30 to -5°C. Volume of the refrigeration room 107: 2500 x 4500 x 2400 mm ³ . Cross-sectional area of the spray tunnel 103: 400 x 400 mm ² . Cross-sectional area of the air outlet 105: 200 x 200 mm ² .

A specimen 109 is placed downstream of the air outlet 105, which is the test section. Air is flowed into the wind tunnel 110, and droplets are sprayed from the spray nozzle 108 toward the specimen. There are two air flow velocity conditions: 20 m/s and 40 m/s. There are two conditions for the droplet diameter sprayed from the spray nozzle 108: 15 μm and 29 μm.

Figures 16 and 17 are photographs showing the results of anti-icing tests.

FIG. 16 shows photographs taken with a camera of the test specimens after the Type 1 and Type 2 anti-icing tests under the first test conditions (air flow rate 20 m/s, droplet diameter 15 μm, power (input power/area of heated region) 1.1 W/cm ² ).

FIG. 17 shows photographs of the test specimens after the Type 1 and Type 2 anti-icing tests under the second test conditions (air flow rate 40 m/s, droplet diameter 15 μm, power (input power/area of heated region) 0.83 W/cm ² ).

Figures 18 and 19 are graphs showing the results of anti-icing tests.

The horizontal axis indicates power, specifically, input power/area of heated area [W/ ^cm2 ]. Since the size of the heated area is different between types 1 and 2 and a simple comparison based on input power is not possible, the evaluation is based on input power/area of heated area. The vertical axis indicates anti-ice effect [%], which is calculated using the following formula:

In the above formula, A _anti-ice [ ^mm2 ] is the average ice area on the front and sides of the specimen after the anti-icing test. _{A ice} [ ^mm2 ] is the average ice area on the front and sides of the specimen after the non-heating ice amount confirmation test. Ideally, these ice areas should be evaluated by the weight of the ice, but since it is not possible to separate ice on the heated and non-heated areas, they are evaluated by image analysis of photographs (Figures 16 and 17).

Figure 18 shows the results of anti-icing tests with an air flow rate of 20 m/s, droplet diameters of 15 μm and 29 μm, and input power changed in several ways. When the power (input power/area of heated region) is at least 0.83 W/ ^cm2 , the anti-icing effect of Type 2 is higher than that of Type 1.

Figure 19 shows the results of anti-icing tests with an air flow rate of 40 m/s, droplet diameters of 15 μm and 29 μm, and multiple changes in input power. When the power (input power/area of heated region) is approximately 0.5 to 1.1 W/ ^cm2 , the anti-icing effect of Type 2 is higher than that of Type 1.

4. Test result 2

Figure 20 is a thermograph showing the results of the windless heat generation test.

Prepare specimens for Case 1 and Case 2. The specimens for Case 1 and Case 2 have different layers connected to the leading edge side conductive part 31 and the trailing edge side conductive part 32. In Case 1, all knife edge surface layers are connected to the leading edge side conductive part 31 and the trailing edge side conductive part 32. In Case 2, a layer (specifically, the two-layer part of the center part 211 in Figure 11) configured in the central part of the thickness direction of one or more selected test pieces is connected to the leading edge side conductive part 31 and the trailing edge side conductive part 32. The specimens for Case 1 and Case 2 are placed in a windless room at room temperature of 10°C, and an input power of 10 W is applied for 30 seconds. The bottom surface of the specimen is photographed with a thermal camera to obtain the surface temperature distribution.

Figure 21 is a graph showing the results of the windless heat generation test.

This graph shows the cross-sectional temperature distribution 30 seconds after the start of current flow at the centre of the bottom surface of the specimen, indicated by the dashed line in Figure 20. The horizontal axis indicates the position of the specimen from the pressure side surface to the suction side surface at the mid-chord position. Pixels 5 to 27 on the horizontal axis correspond to the specimen section. The vertical axis indicates the cross-sectional temperature (°C). The heat generation patterns on the cross sections differed between Case 1 and Case 2. This is thought to be valid for confirmation during anisotropic conductive film (ACF) testing. The temperature in Case 2 is higher overall than in Case 1. The temperatures were particularly high at the leading and trailing edges in Case 2, and it is thought that this influenced the temperature rise in the mid-chord section.

5. Selection of pressure side and suction side layers

Icing on the fan blades 8 of an aircraft jet engine 1 occurs when ice accumulates on the leading edge 24 (particularly in the area from the hub side 26 to the midspan) and pressure surface of the fan blade 8. This phenomenon is caused by the difference in circumferential speed between the hub side 26 and the tip side 27. The hub side 26 of the leading edge 24 has a slow rotational speed, so the amount of ice that accumulates is the greatest, while the tip side 27 has a fast rotational speed, so ice is easily peeled off by centrifugal force and is therefore less likely to accumulate. In addition, when droplets in the air collide with the fan blade 8, a supercooling phenomenon occurs, where droplets rapidly freeze on the leading edge 24 and pressure surface of the fan blade 8.

The above two factors result in ice accumulation that is concentrated in multiple locations on the fan blade 8, making it important to take appropriate anti-icing and de-icing measures to deal with the multiple ice accumulation locations that occur as a result of this complex phenomenon.

For this reason, it is desirable to actively heat the area near the midspan and the positive pressure surface from the hub side 26 of the leading edge 24, where the amount of ice accretion is large. As described above, when a voltage is applied to the current-carrying area of the fan blade body 21 between the leading edge side current-carrying part 31 and the trailing edge side current-carrying part 32, a current flows, and the fan blade body 21 itself generates heat due to its resistance.

For example, a 90° oriented layer that straddles the leading edge 24 and the trailing edge 25 and a layer close to the anti-icing surface (positive pressure surface) are selected and electrified. Also, current may be passed through the positive pressure surface and the negative pressure surface to create a temperature difference or different heat generation areas on the positive pressure surface and the negative pressure surface. To create different heat generation areas, the length of application of the conductive adhesive on the leading and trailing edges and the position of application may be offset. Also, current may be passed through the positive pressure surface and not through the negative pressure surface. Also, the number of layers through which current passes may be increased on the positive pressure surface side compared to the negative pressure surface side, and the number of fibers that generate heat in the conductive fiber itself may be increased on the positive pressure surface side. By selecting the layers that make up the current path, a difference is created in the heat generation temperature or heat generation area on the positive pressure surface and the negative pressure surface, and as a result, anti-icing can be performed with minimal power. The heat generation area and heat generation temperature can be secured with the minimum applied power, and the heat generation temperature on the positive pressure surface and the negative pressure side of the fan blade main body 21 can be set. Specifically, the temperature of the positive pressure surface, where a large amount of ice accumulates, can be made high, and the temperature of the negative pressure surface, where a small amount of ice accumulates, can be made low. This configuration can also function advantageously in the hollow structure that accompanies the recent trend of making fan blades lighter. Furthermore, in the fan blades 8 of the jet engine 1, regardless of the size of the fan blades 8 (regardless of the size of the engine), ice tends to accumulate on the hub side 26 due to the rotation of the fan blades 8, so that the means described in this embodiment can provide an effective anti-icing effect.

6. Brief Summary

The smallest unit (part) that constitutes the fan blade body 21 is the laminated prepreg. The prepreg layer has specifications including the type of resin and carbon fiber that constitutes it, the carbon fiber and resin content, and the thickness. In this embodiment, one or more layers to which electricity is passed are selected. The direction of current flow in the CFRP structure and the area that contributes to heat generation can be specified via a current path that forms a pair between both ends of the carbon fibers of each carbon fiber layer that is aligned in a fixed direction toward the stacking direction of the CFRP.

From a microscopic perspective, the resistance component that excites heat generation in CFRP is proportional to the length between both ends of the carbon fiber layer of the selected layer, and inversely proportional to the thickness of the selected prepreg layer and the carbon fiber content. For example, in a quasi-isotropic configuration in which layers are stacked with different orientations, the resistance component changes and the heat generation temperature also changes due to the different lengths of carbon fibers selected for different layers in the thickness direction. For this reason, in order to generate heat for anti-icing of fan blades, heat generation efficiency is increased by preferentially selecting layers with a short carbon fiber length that straddles the leading and trailing edges.

From a macro perspective, the basic configuration of the fan blade 8 of this embodiment is composed of a power source, a pair of leading edge side current conductors 31 and trailing edge side current conductors 32 that are conductive to the carbon fibers of the selected layer of the CFRP of the fan blade body 21, and a series circuit consisting of the resistance components of the CFRP of the fan blade body 21. Therefore, current flows uniformly within the circuit that constitutes it, and resistance heating is excited by the current flowing according to each resistance component, and the amount of heat generated is determined by the ratio of the resistance values of each resistance component. Regarding the selection of one or more layers, by selecting the carbon fiber layer that straddles the leading edge 24 and trailing edge 25 of the fan blade 9, a current path can be formed at the leading edge 24 (around the hub side 26) where ice is concentrated, and a heat generation area can be set.

A current path is formed consisting of a combination of multiple carbon fiber oriented layers in the stacking thickness direction (e.g., 90°, +45°, -45°), which is expected to increase the heat generation temperature of the leading edge 24 due to an increase in the conductive fiber density on the leading edge 24 side and expand the heat generation area on the surface (positive pressure side) of the fan blade 8.

III. Conductive adhesive

1. Composition of conductive adhesive

Conductive adhesives are materials made by dispersing highly conductive metal particles such as silver, copper, and nickel in a solution of binder resin such as a polymer, which is then cured to form a conductive coating or conductive adhesive layer. The main functions of conductive adhesives are conductivity and adhesiveness, and factors that determine the electrical and mechanical properties mentioned above include curing time, curing temperature, the amount of silver or other metal particles contained, and the size and shape of the metal particles.

For example, as the curing time and temperature increase, the distribution between the metal particles becomes denser and the electrical resistance tends to decrease overall, but the adhesive strength increases. This is thought to be because the solvent in the resin evaporates as the curing time increases, and the paste forms an intimate bond with the substrate as it hardens.

Furthermore, conductive adhesives can be broadly divided into isotropic and anisotropic materials. Isotropic materials conduct electricity in all directions, like solder, but anisotropic materials realize a one-way connection in which current flows only in the direction of compression between opposing electrodes. In the present invention, anisotropic and isotropic materials can be selectively used when selecting layers to form a current path. When using anisotropic conductive films, it is effective when the purpose is to improve the accuracy of the current path for multiple fan blades when selecting layers arranged in the direction of each laminated fiber. In addition, conductive adhesives are used when forming a current path through selected carbon fibers, and the resistance components of the conductive adhesive are selected so that the component ratio is centered on the area that passes through the area where ice is concentrated on the fan blade, thereby obtaining a superior heat generation effect and anti-icing effect.

By bonding the electrode and the fan blade body with a conductive adhesive, the adhesion with the carbon fiber and the contact area are increased, preventing localized temperature rise and poor conductivity at the attachment points between the electrode and the fan blade body and reducing power consumption. This makes it possible to achieve an effective temperature rise even with a low voltage.

In this embodiment, when a current is passed between the pair of leading-edge-side conductive parts 31 and trailing-edge-side conductive parts 32, the resistance value of the conductive adhesive connecting the fan blade body 21 to the leading-edge-side conductive parts 31 (hereinafter referred to as the leading-edge-side conductive adhesive) is set to be higher than the resistance value of the conductive adhesive connecting the fan blade body 21 to the trailing-edge-side conductive parts 32 (hereinafter referred to as the trailing-edge-side conductive adhesive) in order to make the amount of heat generated on the leading edge 24 side of the fan blade body 21 higher than the amount of heat generated on the trailing edge 25 side. For example, the resistance value of the leading-edge-side conductive adhesive used in the experiment was 3×10 ⁻³ to 8×10 ⁻⁴ Ω·cm, and the resistance value of the trailing-edge-side conductive adhesive was 8×10 ⁻⁴ to 2×10 ⁻⁴ Ω·cm. As described above, the resistance component of the conductive adhesive is ensured to have conductivity by using metal particles with good conductivity, so that the resistance value can be appropriately selected based on the average particle size and conductivity of the metal particles and the mechanical properties of the electrode part, and the resistance value described in the present specification is not limited. It is possible to combine the basic specifications required for the fan blade and the current path configuration.

2. Test specimen

Figure 22 shows a schematic of another specimen used in the experiment.

Prepare specimens for layout 1 and layout 2. The specimens for layout 1 and layout 2 are different in the type of conductive adhesive. Both the specimens for layout 1 and layout 2 are CFRP laminates with a span direction of 187 mm, a chord direction of 58.6 mm, and a thickness direction of 4.6 mm. The specimens have a leading edge conductive portion 31A (span direction length 30 mm) and a trailing edge conductive portion 32 (span direction length 30 mm) at the mid-span position, and electricity is applied to the conductive area between the leading edge conductive portion 31 and the trailing edge conductive portion 32. The leading edge conductive portion 31 is connected to the leading edge LE of the specimen using a leading edge conductive adhesive. The trailing edge conductive portion 32 is connected to the trailing edge TE of the specimen using a trailing edge conductive adhesive. In both the test specimens of layout 1 and layout 2, the leading-edge-side conductive adhesive and the trailing-edge-side conductive adhesive are applied to all the stacked prepregs, and all the stacked prepregs are connected to the leading-edge-side conductive portion 31 and the trailing-edge-side conductive portion 32. The area surrounded by the straight lines in the figure is the conductive area between the leading-edge-side conductive portion 31 and the trailing-edge-side conductive portion 32, and is also the heating area and the evaluation area.

Layout 2 is the present embodiment, and the types of the leading-side conductive adhesive and the trailing-side conductive adhesive are different. The resistance value of the leading-side conductive adhesive is higher than the resistance value of the trailing-side conductive adhesive. Specifically, the resistance value of the leading-side conductive adhesive is 3×10 ⁻³ to 8×10 ⁻⁴ Ω·cm, and the resistance value of the trailing-side conductive adhesive is 8×10 ⁻⁴ to 2×10 ⁻⁴ Ω·cm.

Layout 1 is a comparative example, in which the types of the leading-side conductive adhesive and the trailing-side conductive adhesive are the same. Specifically, the resistance values of the leading-side conductive adhesive and the trailing-side conductive adhesive are 3×10 ⁻⁴ to 5×10 ⁻⁵ Ω·cm.

3. Test result 1

Figure 23 is a thermograph showing the test results.

Test specimens of layout 1 and layout 2 are placed in the icing wind tunnel device 100, and air is allowed to flow at an air flow rate of 40 m/s. The same input power (40 W) is applied to the test specimens of layout 1 and layout 2, and the test specimens are photographed with a thermal camera to obtain the surface temperature distribution.

Figure 24 is a graph showing the test results.

This graph shows the surface temperature distribution of the specimen at the mid-span position indicated by the dashed line in Figure 23. The horizontal axis indicates the position of the specimen from the leading edge (0) to the trailing edge (1). The vertical axis indicates the surface temperature (°C). Despite the same input power, layout 2 achieves higher temperatures across the entire range than layout 1, with the leading edge LE achieving a higher temperature than the trailing edge TE. Also, in layout 1, heat is lost from the leading edge due to the convection effect, so the temperature is higher at the trailing edge. On the other hand, in layout 2, despite the same test conditions, a higher temperature is achieved at the leading edge than at the trailing edge.

Figures 25, 26, 27 and 28 are photographs showing the test results.

Figure 25 shows photographs of the test specimens taken with a camera after the results of the anti-icing test for layouts 1 and 2 under the first test conditions (air flow velocity 20 m/s, droplet diameter 15 μm, input power (10 W, 20 W, 40 W)).

Figure 26 shows photographs of the test specimens taken with a camera after the results of the anti-icing test for layouts 1 and 2 under the second test conditions (air flow velocity 20 m/s, droplet diameter 29 μm, input power (10 W, 20 W, 40 W)).

Figure 27 shows photographs of the test specimens taken with a camera after the anti-icing test results for layouts 1 and 2 under the third test conditions (air flow velocity 40 m/s, droplet diameter 15 μm, input power (20 W, 30 W, 50 W)).

Figure 28 shows photographs of the test specimens taken with a camera after the anti-icing test results for layouts 1 and 2 under the fourth test conditions (air flow velocity 40 m/s, droplet diameter 29 μm, input power (20 W, 30 W, 50 W)).

Figures 29 and 30 are graphs showing the test results.

The horizontal axis indicates the input power [W]. The vertical axis indicates the anti-ice effect [%], which is calculated using the above formula (Equation 1).

Figure 29 shows the test results with an air flow velocity of 20 m/s, droplet diameters of 15 μm and 29 μm, and multiple changes to the input power. At all input powers, the anti-icing effect of layout 2 is higher than that of layout 1. Note that while it is not normally possible for the anti-icing effect to be negative, there was a large variation in layout 1, and as a result of averaging, a negative value was generated for the anti-icing effect.

Figure 30 shows the test results with an air flow velocity of 40 m/s, droplet diameters of 15 μm and 29 μm, and multiple changes to the input power. At all input powers, the anti-icing effect of layout 2 is higher than that of layout 1. Note that while it is not normally possible for the anti-icing effect to be negative, there was a large variation in layout 1, and as a result of averaging, the anti-icing effect had a negative value.

4. Test result 2

Figure 31 is a thermograph showing the test results.

Prepare specimens for layout 3 and layout 4. Both specimens for layout 3 and layout 4 are CFRP laminates with a span direction of 187 mm, a chord direction of 58.6 mm, and a thickness direction of 4.6 mm. The specimens have a leading edge side conductive part 31 (span direction length 30 mm) and a trailing edge side conductive part 32 (span direction length 30 mm) at the mid-span position, and the conductive area between the leading edge side conductive part 31 and the trailing edge side conductive part 32 is energized. In layout 3, the leading edge side conductive adhesive and the trailing edge side conductive adhesive are applied to all the stacked prepregs, and all the stacked prepregs are connected to the leading edge side conductive part 31 and the trailing edge side conductive part 32. In layout 4, the leading edge side conductive adhesive and the trailing edge side conductive adhesive are applied only to two layers (90° orientation) in the center of the thickness direction (center of symmetry), and the two layers in the center of the thickness direction are connected to the leading edge side conductive part 31 and the trailing edge side conductive part 32. In this test, the span-direction length of the leading edge side conductive portion 31 and the trailing edge side conductive portion 32 of layouts 3 and 4 is 30 mm (same as above). Test specimens of layouts 3 and 4 are placed in the icing wind tunnel device 100, and air is allowed to flow at a room temperature of -10°C and an air flow rate of 20 m/s. The same input power (20 W) is applied to the test specimens of layouts 3 and 4 for 90 seconds, and the test specimens are photographed with a thermal camera 90 seconds after the start of current flow to obtain the surface temperature distribution.

Figure 5 is a graph showing the test results.

This graph shows the surface temperature distribution of the specimen at the mid-span position indicated by the dashed line in Figure 31. The horizontal axis indicates the position of the specimen from the leading edge (0) to the trailing edge (1). The vertical axis indicates the surface temperature (°C) 90 seconds after the start of current flow. Layout 4 had a higher temperature distribution over the entire area due to heat generation at the leading and trailing edges than layout 3. The reason for this is thought to be that in the formula below, in layout 4, the application area S of the conductive adhesive is narrow (thickness of the conductive adhesive is the same), which increases the resistance R [Ω] and increases the amount of heat.
In addition, in layout 3, the temperature of the leading edge was higher than that of the trailing edge even when ventilation was in progress, but in layout 4, the temperature of the trailing edge was higher than that of the leading edge. Because the area where the conductive adhesive was applied was reduced in layer selection, the resistance of the conductive adhesive used in this study at the leading edge was insufficient to prevent heat loss due to convection heat transfer, leading to this result. However, it is possible to raise the temperature of the leading edge higher than that of the trailing edge even with layer selection by reducing the volume of the conductive adhesive at the leading edge (reducing the applied thickness when the conductive adhesive application area is considered to be the same) or by increasing the ratio of resistance between the leading and trailing edges (resistance value of the leading edge ÷ resistance value of the trailing edge).
Incidentally, under normal temperature and windless conditions, it has been confirmed that in layout 4, like layout 3, the temperature is higher on the leading edge than on the trailing edge.

R = (ρL)/S

Regarding the above-mentioned statement that "it is possible to raise the temperature of the leading edge more than the trailing edge by reducing the volume of the conductive adhesive at the leading edge (reducing the coating thickness when the coating area of the conductive adhesive is considered to be the same) by layer selection," the following test results were obtained.
Figure 40 is a graph showing the measured resistance between the front and rear edges when the thickness of the conductive adhesive applied to the front and rear edges was changed (150 μm, 300 μm, 400 μm, same thickness on front and rear edges) under conditions of -10°C, no wind, and input power of 10 W. As shown in the graph in Figure 40, the resistance increases with decreasing application thickness.
Figure 41 shows the temperature distribution on the side of a CFRP specimen, captured with a thermal camera under the same test conditions as Figure 40, and graphed from the leading edge to the trailing edge of the midspan. This result also shows that reducing the coating thickness results in higher temperatures at both the leading and trailing edges. This is thought to be due to the increased resistance caused by reducing the coating thickness, as shown in Figure 40. The reason why resistance increases when the coating thickness is reduced is thought to be because it becomes more difficult for current to flow, resulting in an increased resistance. This is similar to what happens when the volume of the conductive adhesive is reduced by reducing the coating thickness, resulting in a reduced coating area.

5. Selection of conductive adhesives for pressure side and negative pressure side Icing on the fan blades 8 of the jet engine 1 of an aircraft occurs when ice accumulates on the leading edge 24 (particularly in the region from the hub side 26 to the midspan) and the pressure surface of the fan blade 8. This phenomenon is caused by the difference in the circumferential speed of the hub side 26 and the tip side 27. The hub side 26 of the leading edge 24 has a slow rotational speed, so the amount of ice that accumulates is the largest, while the tip side 27 has a fast rotational speed, so ice is easily peeled off by centrifugal force and is therefore less likely to accumulate. In addition, when droplets in the atmosphere collide with the fan blade 8, a supercooling phenomenon occurs, in which droplets rapidly freeze on the leading edge 24 and the pressure surface of the fan blade 8.

The above two factors result in ice accumulation that is concentrated in multiple locations on the fan blade 8, making it important to take appropriate anti-icing and de-icing measures to deal with the multiple ice accumulation locations that occur as a result of this complex phenomenon.

For this reason, it is desirable to actively heat the area near the midspan and the pressure surface from the hub side 26 of the leading edge 24, where the amount of ice accretion is large. As described above, when a voltage is applied to the current-carrying area of the fan blade body 21 between the leading-edge-side current-carrying portion 31 and the trailing-edge-side current-carrying portion 32, a current flows, and the fan blade body 21 itself generates heat due to the resistance. For this reason, when a current is passed between the pair of leading-edge-side current-carrying portions 31 and trailing-edge-side current-carrying portions 32, it is desirable for the amount of heat generated on the pressure surface side of the fan blade body 21 to be higher than the amount of heat generated on the negative pressure surface side of the fan blade body 21.

As described above, therefore, the conductive adhesive to be applied should be applied in order of decreasing resistance, from leading edge/pressure surface (highest value), leading edge/suction surface, trailing edge/suction surface, and trailing edge/pressure surface (lowest value). For example, the resistance of the leading edge conductive adhesive on the pressure surface side of the fan blade body 21 should be higher than the resistance of the leading edge conductive adhesive on the negative pressure surface side of the fan blade body 21. The resistance of the trailing edge conductive adhesive on the negative pressure surface side of the fan blade body 21 should be higher than the resistance of the trailing edge conductive adhesive on the pressure surface side of the fan blade body 21.

In addition to the resistance value of the conductive adhesive, the board technology used in the equipment industry, rather than electronic component board technology, uses a large current, so the resistance of each part of the fan blade body 21 can be changed by the amount (volume) of conductive adhesive applied, the area bonded to the carbon fiber, and the size of the current path (cross-sectional area of the path).

IV. Layer Selection

11, in the laminated state, both ends of the leading edge 24 side and the trailing edge 25 side of the multiple layers 211, 212, 213, 214, ... 21n in the cord direction are exposed in a layered manner. Therefore, one or more layers selected from the multiple layers 211 (90° orientation), 212 (+45° orientation), 213 (-45° orientation), 214 (0° orientation) ... 21n can be selectively connected to the leading edge side current conducting portion 31 and the trailing edge side current conducting portion 32 via a conductive adhesive. One layer 21n may be connected to the leading edge side current conducting portion 31 and the trailing edge side current conducting portion 32, a selected portion of the layers 21n may be connected to the leading edge side current conducting portion 31 and the trailing edge side current conducting portion 32, or all of the layers 21n may be connected to the leading edge side current conducting portion 31 and the trailing edge side current conducting portion 32.

1. Layer selection ventilation temperature confirmation test

Figure 32 shows a specific example of layer selection used in the experiment.

Four types of specimens are prepared. In layout 1, all exposed layers are coated with a conductive adhesive to make all 90° layers conductive. Layer selection A assumes that the temperature of the leading edge of the specimen is to be increased, and two 90° layers in the center of the specimen are conductive. Layer selection B assumes that the temperature on the surface side of the specimen is to be increased, and two 90° layers close to the surface layer are conductive. Layer selection C (two-layer side) assumes that the temperature of the leading edge is to be increased while the temperature of only one side corresponding to the pressure surface is increased, and two layers are conductive, one 90° layer in the center of the specimen and one 90° layer close to the surface layer (pressure surface). Layer selection C (one-layer side) assumes that the temperature of the leading edge is to be increased while the temperature of only one side corresponding to the pressure surface is increased, and only one layer of the 90° layer in the center of the specimen is conductive.

All test specimens have a leading-edge-side conductive portion 31 (length in the span direction 30 mm) and a trailing-edge-side conductive portion 32 (length in the span direction 30 mm) at the mid-span position, and electricity is passed between the leading-edge-side conductive portion 31 and the trailing-edge-side conductive portion 32. The resistance value of the leading-edge-side conductive adhesive used in the experiment was 3×10 ^-3 to 8×10 ^-4 Ω·cm, and the resistance value of the trailing-edge-side conductive adhesive was 8×10 ^-4 to 2×10 ^-4 Ω·cm. The surface temperature distribution of the test specimen during ventilation was confirmed under conditions of a main flow speed of 20 m/s, input power of 9 W, room temperature of -10°C, and input time of 90 seconds.

Figure 33 is a thermograph showing the results of the layer selection ventilation temperature confirmation test. Figure 34 is a graph showing the results of the layer selection ventilation temperature confirmation test.

The vertical axis of the graph in Figure 34 is the surface temperature of the mid-span dashed line part of the thermograph in Figure 33. The horizontal axis is the chord length from the leading edge to the trailing edge of the specimen, non-dimensionalized.

All layer selections can increase the temperature of the leading edge more than Layout 1 (solid paint). In particular, layer selection A and layer selection C (2nd layer side) have electrical conductivity between the two layers of the leading edge, so the leading edge can be heated in a concentrated manner and the temperature of the leading edge can be increased. . Layer selection B is closest to the surface layer, so it can increase the temperature around the mid-cord of the specimen the highest. Comparing layer selection C (2nd layer side) and layer selection C (1st layer side), layer selection C (2nd layer side) can increase the temperature over the entire area more than layer selection C (1st layer side) because it allows electrical conductivity between the two layers close to the leading edge and surface. By selecting layers, it is possible to efficiently increase the temperature of the leading edge, and furthermore, if one side of the specimen surface is assumed to be the pressure side and the other to be the suction side, it is possible to make the temperature of the pressure side (layer selection C (2nd layer side)) higher than the temperature of the suction side (layer selection C (1st layer side)). Layout 1 (solid coating) was able to make the temperature of the leading edge higher than the trailing edge even when ventilation was in progress, but for layer selection A and layer selection C (2nd layer side and 1st layer side), the temperature of the trailing edge was higher than the leading edge. In layer selection, the conductive adhesive coating area was reduced, so the resistance of the conductive adhesive used at the leading edge was insufficient to prevent heat loss due to convection heat transfer, resulting in this result. However, by reducing the volume of the adhesive (reducing the coating thickness when the conductive adhesive coating area is considered to be the same) and increasing the ratio of resistance between the leading and trailing edges (resistance value of the leading edge ÷ resistance value of the trailing edge), it is possible to make the temperature of the leading edge higher than the trailing edge even with layer selection. Incidentally, it has been confirmed that under normal temperature and no wind conditions, like Layout 1 (solid coating), layer selection A and layer selection C (2nd layer side and 1st layer side) also have a higher temperature at the leading edge than the trailing edge.

Figure 35 is a graph showing the results of the layer selection ventilation temperature confirmation test.

The surface temperature distribution of the specimen during ventilation is confirmed under the conditions of a main flow speed of 20 m/s, input power of 20 W, room temperature of -10°C, and input time of 90 seconds. The only difference between Figure 35 and Figure 34 is the input power. The same function as when the input power is 9 W can be achieved with an input power of 20 W. Layout 1 (solid paint) was able to make the temperature of the leading edge higher than the trailing edge even during ventilation, but with layer selection A and layer selection C (2nd layer side and 1st layer side), the temperature of the trailing edge was higher than the leading edge. Since the conductive adhesive application area was reduced in layer selection, the resistance of the conductive adhesive used in this study at the leading edge against the loss of heat due to convective heat transfer was insufficient, resulting in this result. However, it is possible to raise the temperature of the leading edge higher than the trailing edge even with layer selection by reducing the volume of the adhesive (if the conductive adhesive application area is considered to be the same, the application thickness is reduced) and increasing the ratio of the resistance of the leading and trailing edges (resistance value of the leading edge ÷ resistance value of the trailing edge). Incidentally, under room temperature and windless conditions, it has been confirmed that, like Layout 1 (solid paint), the temperature is higher on the leading edge side than on the trailing edge side for Layer Selection A and Layer Selection C (2nd layer side and 1st layer side).

2. Layer selection anti-icing test

Prepare a test specimen with layout 1 and layer selection A in Figure 32. The test conditions are main flow speed 20 m/s, 40 m/s, droplet diameter 15 μm, input power 20 m/s (10 W, 22 W, 40 W), 40 m/s (20 W, 30 W, 49 W), room temperature -10°C.

Figures 36 and 37 are photographs showing the test results.

Figure 36 shows photographs of the test specimens taken with a camera after the results of the anti-icing test for layout 1 and layer selection A under the test conditions (air flow velocity 20 m/s, droplet diameter 15 μm, input power (10 W, 22 W, 40 W)).

Figure 37 shows photographs of the test specimens taken with a camera after the results of the anti-icing test for layout 1 and layer selection A under different test conditions (air flow velocity 40 m/s, droplet diameter 15 μm, input power (20 W, 30 W, 49 W)).

Figures 38 and 39 are graphs showing the test results.

The horizontal axis indicates the input power [W]. The vertical axis indicates the anti-ice effect [%], which is calculated using the above formula (Equation 1).

Figure 38 shows the results of Figure 36, with test results for an air flow velocity of 20 m/s, droplet diameter of 15 μm, and input power of 10 W, 22 W, and 40 W. At input powers of 22 W and 40 W, the anti-icing effect of layer selection A is higher than that of layout 1.

Figure 39 shows the results of Figure 37, with the air flow velocity of 40 m/s, droplet diameter of 15 μm, and input power of 10 W, 22 W, and 40 W. At input powers of 30 W and 49 W, the anti-icing effect of layer selection A is higher than that of layout 1.

In both Figures 38 and 39, the difference in effectiveness is difficult to see at low power and where the input power is high and the anti-icing effect has reached its limit, but between those, layer selection A has a slightly worse anti-icing effect at low power locations. However, if the weight of ice on the entire test specimen during anti-icing is measured on a scale as "ice weight [g]", including ice that is not in the evaluation area, layer selection A actually has a higher anti-icing effect. It is thought that the unfavorable results were due to the way the ice grows, due to the area calculation. Layer selection A has a greater anti-icing effect than layout 1 (solid color) even with the same input power.

V. Conclusion

This embodiment is based on CFRP, which has excellent mechanical properties and has been adopted for fan blades in recent years, and provides a method for solving the problem of icing from the perspective of material properties and structure. According to this embodiment, it is possible to perform anti-icing and de-icing efficiently with a simple structure. Furthermore, by making it possible to realize the anti-icing function of the fan blades with a minimum of simple additional processing, it is possible to obtain a high level of stability and durability of the anti-icing effect over the long term without adversely affecting the original aerodynamic performance.

This embodiment has the following advantageous effects: it is possible to generate resistive heating in areas where ice is likely to accumulate using the current fan blade specifications (CFRP). It is possible to concentrate resistive heating in areas where ice is likely to accumulate. It is possible to achieve anti-icing functionality with minimal additional processing, and it is easy to maintain and stable over the long term.

The market size of the aircraft industry is expanding year by year, and the proportion of CFRP used in both aircraft and engines is increasing. Anti-icing and de-icing technology in the aviation industry has not changed much from the past, but CFRP is being used in parts that previously used metal, and new anti-icing and de-icing technology is expected to be developed. In this embodiment, the characteristics of CFRP are utilized, and anti-icing and de-icing are possible by adding additional processing to existing CFRP fans without adversely affecting the aerodynamics. In addition, it can be applied to wind turbines used in wind power generation, which has the same icing problem as the aviation industry, and in the automobile industry, where CFRP is becoming more widespread, as a measure against icing in cold regions.

Although each embodiment and each variant of the present technology has been described above, the present technology is not limited to the above-described embodiments, and various modifications can of course be made without departing from the spirit and scope of the present technology.

REFERENCE SIGNS LIST 1: Jet engine 2: Low pressure shaft 4: Intake port 5: Spinner 6: Fan disk 7: Dovetail 8: Fan blade 21: Fan blade body 22: Sheath 23: Guard 24: Leading edge 25: Trailing edge 31: Leading edge side conductive portion 32: Trailing edge side conductive portion 35: Power source 36: Heating area 41: Locking groove 46: Connection terminal 49: Connection terminal 53: Battery 61: Slip ring

Claims (10)

A fan blade disposed on the intake side of the engine,
A fan blade body made of carbon fiber reinforced plastic;
a pair of first and second current-carrying parts for passing a current through a current-carrying region of the fan blade body by passing a current through carbon fibers contained in the carbon fiber reinforced plastic;
Equipped with
when a current flows between the pair of first and second current-carrying portions, a heat amount of the current-carrying region on a first side of the fan blade body is higher than a heat amount of the current-carrying region on a second side of the fan blade body,
The heat generation amount of the current-carrying region on the first side of the fan blade body is higher than the heat generation amount of the current-carrying region on the second side of the fan blade body,
a first-side conductive fiber density, which is a ratio of carbon fibers conducted to the first current-carrying portion relative to a length of the first current-carrying portion in the span direction, is higher than a second-side conductive fiber density, which is a ratio of carbon fibers conducted to the second current-carrying portion relative to a length of the second current-carrying portion in the span direction,
The fan blade body includes a plurality of laminated layers, and the orientation of the carbon fibers included in the plurality of layers is different.
By connecting one or more layers selected from the plurality of layers to the first current-carrying portion and the second current-carrying portion, the conductive fiber density on the first side is higher than the conductive fiber density on the second side.
Fan blade. A fan blade disposed on the intake side of the engine,
A fan blade body made of carbon fiber reinforced plastic;
a pair of first and second current-carrying parts for passing a current through a current-carrying region of the fan blade body by passing a current through carbon fibers contained in the carbon fiber reinforced plastic;
Equipped with
when a current flows between the pair of first and second current-carrying portions, a heat amount of the current-carrying region on a first side of the fan blade body is higher than a heat amount of the current-carrying region on a second side of the fan blade body,
The fan blade body includes a plurality of laminated layers.
One or more layers selected from the plurality of layers are connected to the first current-carrying portion and the second current-carrying portion ,
The one or more layers include
A fan blade comprising: a first layer comprising carbon fibers oriented in a first direction that is positively inclined with respect to both the span direction and the chord direction; and/or a second layer comprising carbon fibers oriented in a second direction that is negatively inclined with respect to both the span direction and the chord direction. A fan blade disposed on the intake side of the engine,
A fan blade body made of carbon fiber reinforced plastic;
a pair of first and second current-carrying parts for passing a current through a current-carrying region of the fan blade body by passing a current through carbon fibers contained in the carbon fiber reinforced plastic;
Equipped with
when a current flows between the pair of first and second current-carrying portions, a heat amount of the current-carrying region on a first side of the fan blade body is higher than a heat amount of the current-carrying region on a second side of the fan blade body,
A fan blade, wherein a length in a span direction of the second current-carrying portion is longer than a length in the span direction of the first current-carrying portion. A fan blade disposed on the intake side of the engine,
A fan blade body made of carbon fiber reinforced plastic;
a pair of first and second current-carrying parts for passing a current through a current-carrying region of the fan blade body by passing a current through carbon fibers contained in the carbon fiber reinforced plastic;
Equipped with
when a current flows between the pair of first and second current-carrying portions, a heat generation amount of the current-carrying region on a first side of the fan blade body is higher than a heat generation amount of the current-carrying region on a second side of the fan blade body,
The fan blade body includes a plurality of laminated layers,
a layer on a pressure surface side selected from the plurality of layers is connected to the first current conducting portion and the second current conducting portion,
a fan blade, wherein when a current flows between the pair of first and second current-carrying portions, an amount of heat generated on a pressure surface side of the fan blade body is higher than an amount of heat generated on a suction surface side of the fan blade body. A fan blade disposed on the intake side of the engine,
A fan blade body made of carbon fiber reinforced plastic;
a pair of first and second current-carrying portions for passing a current through a current-carrying region of the fan blade body by passing a current through carbon fibers contained in the carbon fiber reinforced plastic;
a first side conductive adhesive and a second side conductive adhesive that connect the fan blade body to the first current-carrying portion and the second current-carrying portion;
Equipped with
when a current flows between the pair of first and second current-carrying portions, a heat generation amount of the current-carrying region on a first side of the fan blade body is higher than a heat generation amount of the current-carrying region on a second side of the fan blade body,
The heat generation amount of the current-carrying region on the first side of the fan blade body is higher than the heat generation amount of the current-carrying region on the second side of the fan blade body,
a resistance value of the first side conductive adhesive being higher than a resistance value of the second side conductive adhesive. 6. A fan blade as claimed in claim 5 ,
The fan blade body includes a plurality of laminated layers.
The first side conductive adhesive and the second side conductive adhesive connect one or more layers selected from the plurality of layers to the first current-carrying portion and the second current-carrying portion. 7. A fan blade according to claim 5 or 6 ,
a resistance value of the first side conductive adhesive on a pressure surface side of the fan blade body is higher than a resistance value of the first side conductive adhesive on a suction surface side of the fan blade body,
A fan blade, wherein a resistance value of the second side conductive adhesive on the pressure side is lower than a resistance value of the second side conductive adhesive on the suction side. A fan blade according to any one of claims 1 to 7 ,
the first side is a leading edge side of the fan blade body;
The second side is a trailing edge side of the fan blade body. A rotation axis;
A fan disk provided on the intake side of the rotating shaft;
A fan blade according to any one of claims 1 to 8 , removably attached to the fan disk;
a pair of connection terminals provided on the fan disk side and the fan blade side for each of the first current-carrying portion and the second current-carrying portion, the connection terminals being electrically connected to each other when the fan blade is attached to the fan disk, for conducting electricity between a power source on the fan disk side and the first current-carrying portion and the second current-carrying portion;
An engine comprising: A plate-shaped member made of carbon fiber reinforced plastic and having an ice formation region due to a gas flow;
a pair of first and second current-carrying parts provided on a first side and a second side of the plate-shaped member, respectively, to include the ice-accretion region, for causing a current to flow through the carbon fibers contained in the carbon fiber reinforced plastic to cause a current to flow through the current-carrying region of the plate-shaped member;
a first side conductive adhesive and a second side conductive adhesive that connect the plate-like member to the first current-carrying portion and the second current-carrying portion;
Equipped with
a heat generation amount of the current-carrying region on the first side of the plate-like member is higher than a heat generation amount of the current-carrying region on the second side of the plate-like member,
The heat generation amount of the current-carrying region on the first side of the plate-like member is higher than the heat generation amount of the current-carrying region on the second side of the plate-like member,
a resistance value of the first-side conductive adhesive is higher than a resistance value of the second-side conductive adhesive.
Structure with anti-icing and de-icing functions.

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