JP5481946B2 - Noise reduction device - Google Patents

Description

  The present invention relates to a noise reduction device that includes a plurality of micro jet nozzles arranged around a main jet nozzle of a jet engine, and reduces noise by injecting fluid from the micro jet nozzles toward a jet flow. .

For example, Non-Patent Document 1 describes a noise reduction device including a plurality of micro jet nozzles arranged around a main jet nozzle of a jet engine.
This noise reduction device is intended to reduce noise caused by a jet flow by injecting air from each micro jet nozzle toward the jet flow.

On the other hand, Non-Patent Document 1 proposes a technique for further reducing noise by arranging the micro jet nozzle in an inclined manner with respect to the axis of the main jet nozzle in the above-described noise reduction device.
By arranging the micro jet nozzle so as to be deeply inclined with respect to the axis of the main jet nozzle in this way, mixing of the air jetted from the micro jet nozzle and the jet flow is promoted, thereby further reducing noise. Is possible.

Brenton Greska, Anjaneyulu Krothapalli, John M. Seiner, Bernard Jansen, Lawrence Ukeiley, [The Effects of Microjet Injection on an F404 Jet Engine], 11th AIAA / CEAS Aeroacoustics Conference (26th AIAA Aeroacoustics Conference) 23-25 May 2005, Monterey, California, AIAA 2005-3047

  However, when the micro jet nozzle is disposed so as to be deeply inclined with respect to the axis of the main jet nozzle, the micro jet nozzle projects toward the outside of the main jet nozzle. For this reason, the nacelle resistance in a jet engine increases. Therefore, when the micro jet nozzle is disposed so as to be deeply inclined with respect to the axis of the main jet nozzle, noise can be reduced but the aerodynamic performance of the jet engine is deteriorated.

  The present invention has been made in view of the above-described problems, and an object thereof is to further reduce noise without deteriorating the aerodynamic performance of a jet engine.

  The present invention adopts the following configuration as means for solving the above-described problems.

  A first invention is a noise reduction device that includes a plurality of micro jet nozzles arranged around a main jet nozzle of a jet engine, and that reduces noise by injecting fluid from the micro jet nozzle toward the jet flow. Thus, a configuration is adopted in which the opening end surface of the micro jet nozzle is inclined toward the jet flow with respect to an orthogonal plane orthogonal to the extending direction of the micro jet nozzle.

  A second invention employs a configuration in which, in the first invention, the opening end face of the micro jet nozzle is further inclined in the circumferential direction of the main jet nozzle.

  According to a third invention, in the second invention, a configuration is adopted in which the open end faces of all the microjet nozzles are inclined in one circumferential direction of the main jet nozzle.

  According to a fourth aspect of the present invention, in the second aspect of the invention, the micro jet nozzle in which the opening end surface is inclined in one direction in the circumferential direction of the main jet nozzle, and the opening end surface in the circumferential direction of the main jet nozzle. A configuration is adopted in which the microjet nozzle is inclined in the other direction.

  According to a fifth invention, in any one of the first to fourth inventions, a configuration is adopted in which the shape of the opening end surface viewed from the extending direction of the microjet nozzle is a semicircular shape.

  In a sixth aspect of the present invention, in any one of the first to fifth aspects of the present invention, a configuration is provided in which a guide portion is provided that guides the fluid ejected from the opening end surface while further inclining with respect to the orthogonal plane.

According to the present invention, the opening end face of the micro jet nozzle is inclined toward the jet flow with respect to the orthogonal plane orthogonal to the extending direction of the micro jet nozzle. The jet direction of the fluid jetted from the opening end face is inclined deeper than the micro jet nozzle itself with respect to the axis of the main jet nozzle. Therefore, according to the present invention, it is possible to deepen the entrance angle of the fluid jetted from the microjet nozzle with respect to the jet flow without deeply tilting the microjet nozzle itself with respect to the axis of the main jet nozzle.
Therefore, according to the present invention, it is possible to further reduce noise without reducing the aerodynamic performance of the jet engine.

It is a schematic block diagram of a jet engine provided with the noise reduction apparatus in 1st Embodiment of this invention. It is a schematic diagram which shows schematic structure of the noise reduction apparatus in 1st Embodiment of this invention, and is the figure seen from the direction orthogonal to the axis | shaft of a main jet nozzle. It is a schematic diagram which shows schematic structure of the noise reduction apparatus in 1st Embodiment of this invention, and is the figure seen from the axial direction of the main jet nozzle. It is the schematic diagram which expanded the opening end surface of the micro jet nozzle with which the noise reduction apparatus in 1st Embodiment of this invention is provided. It is a schematic diagram for demonstrating the principle of the noise reduction apparatus in 1st Embodiment of this invention. It is a schematic diagram which shows schematic structure of the noise reduction apparatus in 2nd Embodiment of this invention, and is the figure seen from the axial direction of the main jet nozzle. It is the schematic diagram which expanded the opening end surface of the micro jet nozzle with which the noise reduction apparatus in 2nd Embodiment of this invention is provided. It is the figure which looked at the micro jet nozzle with which the noise reduction apparatus in 2nd Embodiment of this invention is provided from the extending direction. It is a schematic diagram which shows schematic structure of the noise reduction apparatus in 3rd Embodiment of this invention, and is the figure seen from the axial direction of the main jet nozzle. It is a schematic diagram which shows schematic structure of the noise reduction apparatus in 4th Embodiment of this invention, and is the figure seen from the axial direction of the main jet nozzle. It is the figure which looked at the micro jet nozzle with which the noise reduction apparatus in 4th Embodiment of this invention is provided from the extending direction. It is a figure which shows the modification of the noise reduction apparatus of this invention, and is the figure which looked at the micro jet nozzle from the extending direction. It is a figure which shows the modification of the noise reduction apparatus of this invention, and is the figure which looked at the micro jet nozzle from the side. It is a figure which shows the modification of the noise reduction apparatus of this invention, and is the figure which looked at the micro jet nozzle from the extending direction.

  Hereinafter, an embodiment of a noise reduction device according to the present invention will be described with reference to the drawings. In the following drawings, the scale of each member is appropriately changed in order to make each member a recognizable size.

(First embodiment)
FIG. 1 is a schematic configuration diagram of a jet engine 10 including a noise reduction device S1 of the present embodiment.
As shown in this figure, the jet engine 10 includes a fan 20, a compressor 30, a combustor 40, a turbine 50, and a main jet nozzle N.

  2 and 3 are schematic views showing a schematic configuration of the noise reduction device S1 of the present embodiment. FIG. 2 is a view as seen from a direction perpendicular to the axis L of the main jet nozzle, and FIG. It is the figure seen from the axis L direction. As shown in these drawings, the noise reduction device S1 of the present embodiment includes a micro jet nozzle 1 and a flow rate adjusting valve 2.

A plurality of micro jet nozzles 1 are arranged around the main jet nozzle N of the jet engine, and are fixed along the outer wall surface of the main jet nozzle N. These micro jet nozzles 1 inject air Y (fluid) with respect to the jet stream X injected from the main jet nozzle N from the opening end surface 1a.
These micro jet nozzles 1 are connected to a compressor (not shown) included in the jet engine, and inject air supplied from the compressor.

FIG. 4 is an enlarged schematic view of the opening end face 1a of the microjet nozzle 1. As shown in FIG. As shown in this figure, in the noise reduction device S1 of the present embodiment, the opening end face 1a of each micro jet nozzle 1 is directed toward the jet flow X with respect to the orthogonal plane M orthogonal to the extending direction L1 of the micro jet nozzle 1. Is inclined. More specifically, in the noise reduction device S1 of the present embodiment, the opening end face 1a of the microjet nozzle 1 is inclined with respect to the orthogonal plane M by an angle α.
Here, the injection angle θ of the air Y with respect to the axis L of the main jet nozzle N (axis L2 parallel to the axis L in FIG. 4) is lower when the inclination angle with respect to the axis L of the microjet nozzle 1 is β. It can be approximated by equation (1).
θ ≒ 0.5 ・ (α + 3β) …… (1)

Here, when the deflection angle due to the inclination of the opening end face 1a of the microjet nozzle 1 is γ, the deflection angle γ can be approximated by the following equation (2).
γ ≒ 0.5 ・ α …… (2)

If the effect drawn into the jet stream X is an angle η, the angle η can be approximated by the following equation (3).
η ≒ 0.5 ・ β …… (3)

  4 that the injection angle θ can be approximated by the sum of the inclination angle β of the microjet nozzle, the inclination angle α of the opening end face 1a, and the angle η. From this, it can be understood that the formula (1) can be easily derived.

  The reason why the deflection angle γ is generated is that a static pressure distribution in the microjet nozzle is generated by inclining the opening end face. The fluid has a property that the pressure constant surface tends to flow along, but when the static pressure distribution in the micro jet nozzle is generated as described above, the pressure constant surface is inclined as shown in FIG. As a result, a deflection angle γ is generated and the flow direction of the air Y is deflected.

  As described above, the principle of injecting the air Y by inclining the opening end face 1a of the microjet nozzle 1 is described in “44th AIAA Aerospace Sciences Meeting, AIAA 2006-485, Further Steps in LES-Based Noise Prediction for Complex Jets ".

As can be seen from the equation (1), when the opening end surface 1a of the micro jet nozzle 1 is inclined in the jet flow X direction with respect to the orthogonal surface M, the air Y is injected onto the axis L of the main jet nozzle N. The angle θ is larger than the inclination angle β with respect to the axis L of the microjet nozzle 1.
This means that the injection direction of the air Y injected from the micro jet nozzle 1 is inclined deeper than the micro jet nozzle 1 itself with respect to the axis L of the main jet nozzle N.

  Returning to FIG. 2 and FIG. 3, the flow rate adjustment valve 2 adjusts the flow rate of the air Y supplied to the micro jet nozzle 1. The flow rate adjusting valve 2 is configured to be able to stop the supply of the air Y to the micro jet nozzle 1. Further, the flow rate control valve 2 does not need to be provided for each microjet nozzle 1, and a configuration in which all or some of the flow rate control valves 2 shown in FIGS. 2 and 3 are combined may be adopted. Is possible.

  In the noise reduction device S1 of the present embodiment configured as described above, air Y is supplied from the compressor to each microjet nozzle 1 by opening the flow rate control valve 2. And the air Y supplied to each micro jet nozzle 1 is injected from the opening end surface 1a, and is mixed with the jet stream X. FIG. Then, the air Y from the opening end face 1a is injected into the mixed layer of the jet stream X, whereby noise caused by the jet stream X is reduced.

Here, according to the noise reduction device S1 of the present embodiment, the opening end face 1a of the microjet nozzle 1 is directed toward the jet flow X with respect to the orthogonal plane M orthogonal to the extending direction L1 of the microjet nozzle 1. It is inclined. For this reason, the injection direction of the air Y injected from the opening end face 1a is inclined deeper than the micro jet nozzle 1 itself with respect to the axis L of the main jet nozzle N. Therefore, according to the noise reduction device S1 of the present embodiment, the jet flow X of the air Y injected from the micro jet nozzle 1 without deeply tilting the micro jet nozzle 1 itself with respect to the axis L of the main jet nozzle N. It becomes possible to deepen the approach angle with respect to.
Thus, according to the noise reduction device S1 of the present embodiment, the microjet nozzle 1 is fixed along the outer wall of the main jet nozzle N to suppress an increase in nacelle resistance, and further, the jet flow of the air Y By increasing the approach angle with respect to X, a large noise reduction effect can be obtained.
Therefore, according to the noise reduction device S1 of this embodiment, it is possible to further reduce noise without reducing the aerodynamic performance of the jet engine.

  In addition, when the approach angle of the air Y with respect to the jet stream X is too deep or too shallow, the noise reduction effect is low, and about 60 ° has the highest noise reduction effect. Therefore, the inclination angle α of the opening end face 1a is preferably set so that the approach angle of the air Y with respect to the jet flow X is 60 ° based on the equation (1).

(Second Embodiment)
Next, a second embodiment of the present invention will be described. In the description of the second embodiment, the description of the same parts as in the first embodiment will be omitted or simplified.

  FIG. 6 is a schematic diagram showing a schematic configuration of the noise reduction device S2 of the present embodiment, and is a view seen from the direction of the axis L of the main jet nozzle N. Moreover, FIG. 7 is the schematic diagram which expanded the opening end surface 1a of the micro jet nozzle 1 with which noise reduction apparatus S2 of this embodiment is provided. Moreover, FIG. 8 is the figure which looked at the micro jet nozzle 1 with which noise reduction apparatus S2 of this embodiment is provided from the extending direction L1.

As shown in FIG. 8, in the noise reduction device S2 of the present embodiment, the opening end surface 1a of the micro jet nozzle 1 is further angled γ in the circumferential direction of the main jet nozzle N in addition to the first embodiment. It is inclined.
Further, in the noise reduction device S2 of the present embodiment, as shown in FIG. 6, the open end faces 1a of all the microjet nozzles 1 are inclined in one circumferential direction of the main jet nozzle N.

The injection direction of the air Y in the noise reduction device S2 of the present embodiment is perpendicular to the axis L of the main jet nozzle N (axis L2 parallel to the axis L in FIG. 7), as shown in FIG. It is defined by the inclination angle θr in the plane and the inclination angle θt in the horizontal plane.
Further, the inclination angle θr can be approximated by the following expression (2), and the inclination angle θt can be approximated by the following expression (3).
θr≈atan {tan (θ) · cos (γ)} (2)
θt≈atan {tan (θ) · sin (γ)} (3)

  According to the noise reduction device S2 of the present embodiment that employs such a configuration, the injection range of the jet stream X of the air Y injected from the opening end face 1a of each microjet nozzle 1 is widened. For this reason, it becomes possible to aim at reduction of the noise resulting from the jet stream X more efficiently. Therefore, for example, in the case of aiming at the same level of noise reduction as the noise reduction device S2 of the first embodiment, the number of microjet nozzles 1 can be reduced.

(Third embodiment)
Next, a third embodiment of the present invention will be described. In the description of the third embodiment, the description of the same parts as those of the first embodiment or the second embodiment is omitted or simplified.

FIG. 9 is a schematic diagram showing a schematic configuration of the noise reduction device S3 of the present embodiment, and is a view seen from the direction of the axis L of the main jet nozzle N.
As shown in this figure, in the noise reduction device S3 of the present embodiment, in the circumferential direction of the main jet nozzle N, the inclination direction in the circumferential direction of the microjet nozzle 1 is changed every 90 ° range.
That is, the noise reduction device S3 of the present embodiment includes a micro jet nozzle 1 whose opening end surface 1a is inclined in one circumferential direction of the main jet nozzle N, and an opening end surface 1a other than the circumferential direction of the main jet nozzle N. And a micro jet nozzle 1 inclined in the direction.

According to the noise reduction device S3 of the present embodiment that employs such a configuration, the jet of air Y that is injected from the open end face 1a of each microjet nozzle 1 as in the noise reduction device S2 of the second embodiment. The injection range for the mixed layer of the flow X is widened, and efficient noise reduction can be realized.
In addition to this, according to the noise reduction device S3 of the present embodiment, the air Y injected from the micro jet nozzle 1 whose opening end face 1a is inclined in one circumferential direction of the main jet nozzle N, and the opening end face 1a. Is injected in a direction in which the air Y injected from the micro jet nozzle 1 inclined in the other direction of the circumferential direction of the main jet nozzle N collides with the air Y, it is suppressed that the jet stream X swirls by the air Y, It becomes possible to suppress the thrust loss of the jet engine.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described. In the description of the fourth embodiment, the description of the same parts as in any of the first to third embodiments will be omitted or simplified.

FIG. 10 is a schematic diagram showing a schematic configuration of the noise reduction device S4 of the present embodiment, as viewed from the direction of the axis L of the main jet nozzle N. Moreover, FIG. 11 is the schematic diagram which looked at the micro jet nozzle 1 with which noise reduction apparatus S4 of this embodiment is provided from the extending direction L1.
As shown in these drawings, in the noise reduction device S4 of the present embodiment, in the circumferential direction of the main jet nozzle N, the inclination direction in the circumferential direction of the microjet nozzle 1 is changed alternately.
That is, the noise reduction device S4 of the present embodiment is similar to the noise reduction device S3 of the third embodiment, and the micro jet nozzle 1 whose opening end face 1a is inclined in one circumferential direction of the main jet nozzle N. And the micro jet nozzle 1 whose opening end face 1a is inclined in the other direction of the circumferential direction of the main jet nozzle N.

  And according to the noise reduction apparatus S4 of this embodiment which employ | adopts such a structure, while aiming at efficient noise reduction similarly to the noise reduction apparatus S3 of the said 2nd Embodiment, thrust loss of a jet engine Can be suppressed.

  As mentioned above, although preferred embodiment of this invention was described referring drawings, this invention is not limited to the said embodiment. Various shapes, combinations, and the like of the constituent members shown in the above-described embodiments are examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

For example, in the above-described embodiment, the configuration in which the shape of the opening end surface 1a viewed from the extending direction L1 of the microjet nozzle 1 is circular has been described.
However, the present invention is not limited to this, and as shown in FIG. 12, it is also possible to adopt a configuration in which the shape of the open end face 1a viewed from the extending direction L1 of the microjet nozzle 1 is a semicircular shape. it can.
By adopting such a configuration, the micro jet nozzle 1 can be shaped to be more closely attached to the main jet nozzle N, and the change in the injection angle of the air Y due to the inclination of the opening end face 1a is increased. It becomes possible.

In addition to the configuration shown in FIG. 11, as shown in FIGS. 13 and 14, an arc-shaped guide portion 3 from the opening end face 1 a toward the main jet nozzle N is installed, and the air Y injected from the opening end face 1 a May be guided while being further inclined with respect to the orthogonal plane M.
By providing such a guide part 3 in the noise reduction device, the jet angle of the air Y can be made deeper with respect to the axis L due to the Coanda effect by the guide part 3.

Moreover, in the said embodiment, as shown in FIG. 2 etc., the structure in which the 16 micro jet nozzles 1 in total were installed was demonstrated.
However, the present invention is not limited to this, and the number of microjet nozzles 1 can be arbitrarily changed according to the required noise reduction effect.

Moreover, in the said embodiment, the structure whose opening end surface 1a was a plane was demonstrated.
However, the present invention is not limited to this, and the opening end surface may be a curved surface or a bent surface.

Moreover, in the said embodiment, the structure which uses the air Y as a fluid of this invention was demonstrated.
However, the present invention is not limited to this, and it is possible to use other fluids such as water vapor as the fluid.

Moreover, in the said embodiment, the compressed air produced | generated by the compressor of the jet engine was supplied to the micro jet nozzle 1, and the structure which does not require the noise reduction apparatus to be provided with the fluid supply apparatus was demonstrated.
However, the present invention is not limited to this, and a configuration in which the noise reduction device is separately provided with a fluid supply device may be employed. In this case, the flow control valve 2 is not necessarily installed.

  S1 to S4 ... Noise reduction device, 1 ... Micro jet nozzle, 1a ... Open end face, 2 ... Flow control valve, 3 ... Guide, X ... Jet flow, Y ... Air (fluid), M ... Orthogonal plane, N ... Main jet nozzle, L ... Axis, L1 ... Extending direction

Claims (5)

A noise reduction device comprising a plurality of micro jet nozzles arranged around a main jet nozzle of a jet engine, and reducing noise by injecting a fluid from the micro jet nozzles toward a jet flow,
The opening end face of the micro jet nozzle is inclined toward the jet flow with respect to an orthogonal plane orthogonal to the extending direction of the micro jet nozzle ,
The noise reduction device according to claim 1, wherein the shape of the opening end surface viewed from the extending direction of the microjet nozzle is a semicircular shape . A noise reduction device comprising a plurality of micro jet nozzles arranged around a main jet nozzle of a jet engine, and reducing noise by injecting a fluid from the micro jet nozzles toward a jet flow,
The opening end face of the micro jet nozzle is inclined toward the jet flow with respect to an orthogonal plane orthogonal to the extending direction of the micro jet nozzle ,
A noise reduction device comprising: a guide portion that guides the fluid ejected from the opening end surface by further inclining with respect to the orthogonal surface . The noise reduction device according to claim 1 or 2 , wherein an opening end face of the micro jet nozzle is further inclined in a circumferential direction of the main jet nozzle. The noise reduction device according to claim 3 , wherein the opening end faces of all the micro jet nozzles are inclined in one circumferential direction of the main jet nozzle. The micro jet nozzle in which the opening end surface is inclined in one direction in the circumferential direction of the main jet nozzle, and the micro jet nozzle in which the opening end surface is inclined in the other direction in the circumferential direction of the main jet nozzle. The noise reduction device according to claim 3 , wherein the noise reduction device is provided.

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