JP7807733B2 - Fluid Mixing Device - Google Patents

Description

The present invention relates to a fluid mixing device that mixes multiple fluids.

Conventionally, a micro-bubble generator for generating micro-bubbles in a liquid includes a main body, a swirling flow generating section that generates a swirling flow of water, a flow velocity increasing section that increases the flow velocity of the swirling flow, and a gas inlet section that forms an air inlet path that communicates with the water flow path. In this micro-bubble generator, combinations of swirling flow generating sections and corresponding flow velocity increasing sections are arranged in parallel at multiple locations when viewed in the direction of the central axis of the main body (see, for example, Patent Document 1).

JP 2015-150548 A

In the above-mentioned conventional technology, when a mixed fluid of liquid (water) and gas (air) is produced, air is introduced from outside the water due to the accelerated swirling flow, causing the water and air to merge. Therefore, the merger of water and air becomes an outer entrainment merger, in which the air moving axially across the water surface area is entrained by the accelerated swirling flow of water flowing axially. This results in low entrainment efficiency when air is entrained inside the water flowing as an accelerated swirling flow, preventing improvements in the mixing and stirring performance of the water and air.

The present invention was made in response to the above-mentioned problems, and aims to provide a fluid mixing device that improves the mixing and stirring performance of multiple fluids when mixing multiple fluids to produce a mixed fluid.

To achieve the above object, the present invention provides a fluid mixing device for mixing multiple fluids, comprising a main body member, an input port member, and a fluid path forming member. The main body member has a component mounting portion and a fluid mixing portion on a main body central axis along the flow direction of the multiple fluids. The input port member is fixed to the component mounting portion and has a first input port for introducing a first fluid from the outside and a second input port for introducing a second fluid different from the first fluid from the outside. The fluid path forming member is fixed downstream of the input port member and has a nozzle hole through which the first fluid flows from the first input port and a straight hole through which the second fluid flows from the second input port. The nozzle hole is a plurality of holes arranged in a tapered cone shape, and a first inlet and a first outlet for the first fluid are connected by a biaxially inclined hole whose center axis is inclined radially and circumferentially relative to the main body central axis. The straight hole is formed by connecting the second inlet and second outlet for the second fluid with an axial hole whose central axis is aligned with the central axis of the main body. The fluid path forming member has a tip surface formed with a plurality of first outlets opened circumferentially and a second outlet opened at the center surrounded by the plurality of first outlets, and the tip surface is disposed in the fluid inlet region of the fluid mixing section. The nozzle hole of the invention according to claim 1 is a spiral nozzle hole having an inner surface protrusion that protrudes spirally from the first inlet for the first fluid toward the first outlet on the inner surface of the nozzle hole inclined on two axes. The straight hole of the invention according to claim 8 has a buffer hole at the position of the second outlet, the inner diameter of which is larger than the inner diameter of the straight hole.

By employing the above-described means, a swirling flow with increased velocity is ejected from the first outlet for the first fluid on the tip surface of the fluid path-forming member toward the fluid inlet region of the fluid mixing section, generating negative pressure in the central region of the tip surface of the fluid path-forming member. Because this negative pressure-generating region coincides with the position of the second outlet for the second fluid, the second fluid is subjected to a negative pressure pulling force. Therefore, the confluence of the first and second fluids becomes an inner suction confluence in which the second fluid is sucked toward the inner center of the first fluid, and the second fluid is efficiently drawn into the first fluid being ejected by the swirling flow, resulting in mixing and stirring. As a result, a fluid mixing device can be provided that improves the mixing and stirring performance of multiple fluids when mixing multiple fluids to produce a mixed fluid. The invention of claim 1 can quickly start mixing the first and second fluids in the fluid inlet region of the fluid mixing section, and can improve the mixing and stirring performance of the first and second fluids in the fluid mixing section. In addition, the improved mixing and stirring performance in the fluid mixing section allows the axial length of the fluid mixing section to be shortened, contributing to a more compact fluid mixing device. The invention according to claim 8 allows the flow velocity of the second fluid sucked toward the inner center of the combined swirling flow to be adjusted to match the flow velocity of the combined swirling flow of the first fluid. Therefore, in the fluid inlet region of the fluid mixing section, the second fluid flows toward the inner center of the combined swirling flow of the first fluid at an appropriate velocity, improving the merging performance of the first and second fluids.

1 is an overall front view showing the external appearance of a fluid mixing device according to a first embodiment; FIG. 2 is a side view showing the configuration of the fluid mixing device of the first embodiment as viewed from the input port member side. 2 is a cross-sectional view taken along line II of FIG. 1, showing the internal configuration of the fluid mixing device of the first embodiment. FIG. 2. FIG. 3 is a cross-sectional view taken along line II-II in FIG. 2, showing the internal configuration of the fluid mixing device of the first embodiment. FIG. 2 is an enlarged cross-sectional view showing a main body member of the fluid mixing device of the first embodiment. FIG. 2 is a diagram showing an input port member of the fluid mixing device of the first embodiment. FIG. 2 is a front view showing a fluid path forming member of the fluid mixing device of the first embodiment. 10 is a cross-sectional view taken along the line III-III in FIG. 9 showing the fluid path forming member of the fluid mixing device of the first embodiment. FIG. 8 is a side view showing the configuration of the fluid path forming member shown in FIG. 7 as viewed from the input side. FIG. 9 is a longitudinal cross-sectional view showing a state in which a hole-shaped pin is inserted into one of the spiral nozzle holes formed in the fluid path forming member shown in FIG. 8. FIG. 11A and 11B are front and tip views showing the hole-shaped pin of FIG. 10, in which the hole shape of the spiral nozzle hole is represented by an inverted shape. FIG. 11 is a perspective view showing the hole shape pin of FIG. 10, which represents the hole shape of the spiral nozzle hole by an inverted shape. 10 is a perspective view showing the configuration of the tip end surface of the fluid path forming member as viewed from the fluid mixing portion side. FIG. 10 is a velocity vector diagram showing velocity vectors in the analysis results using the analytical model of the fluid mixing device of Example 1. 1 is a streamline diagram showing the flow lines of water and air in the analysis results using the analytical model of the fluid mixer of Example 1. FIG. FIG. 1 is an air flow diagram showing the flow lines of only air in the analysis results using the analytical model of the fluid mixer of Example 1. FIG. 10 is an overall front view showing the external appearance of a fluid mixing device according to a second embodiment. FIG. 10 is a vertical cross-sectional view showing the internal configuration of a fluid mixing device according to a second embodiment.

Below, an embodiment of the fluid mixing device according to the present invention will be described based on Examples 1 and 2 shown in the drawings.

The fluid mixing apparatus 1A of Example 1 is an example of a fluid mixing apparatus that mixes multiple fluids, in which the first fluid is water and the second fluid is air, and the water and air are mixed to produce a gas-liquid multiphase fluid. Here, "fluid" is used as a general term for liquids and gases that can flow while freely changing shape. "Multiple fluids" refers to two or more types of fluids with different physical properties (viscosity, compressibility, etc.), which are the characteristics of the fluids themselves, and includes combinations of different liquids and combinations of different gases in addition to combinations of liquid and gas. An example of a combination of different liquids is the combination of water and oil.

First, with reference to Figures 1 to 4, we will explain the overall configuration of a fluid mixing device 1A that generates a gas-liquid multiphase fluid by mixing air with water supplied at a predetermined water pressure. Here, "water" refers to an incompressible liquid with a higher viscosity than air, such as tap water. "Air" is an example of a compressible gas with a lower viscosity than water.

As shown in Figures 1 to 4, the fluid mixing device 1A comprises a main body member 10, an input port member 20, and a fluid path forming member 30. Each of the members 10, 20, and 30 is manufactured by molding using a resin molding machine using a synthetic resin material selected, for example, depending on the usage environment and type of fluid. Of course, the materials used for the members 10, 20, and 30 may also be metal, or a composite of metal and synthetic resin, in addition to synthetic resin.

The main body member 10 is a cylindrical member that has a component mounting section 11, a fluid mixing section 12, a diffuser section 13, and a straight pipe section 14 on the main body central axis CL along the flow direction of water and air (flow direction from left to right in Figure 1). The main body member 10 of Example 1 is a cylindrical member with a diameter of approximately 30 mm and an axial length of approximately 90 mm, taking into consideration its use in connecting a water supply piping component to the input side.

As shown in Figures 3 and 4, the input port member 20 is fastened to the member mounting portion 11 by screws. The input port member 20 has a first input port 21 that introduces water from the outside and a second input port 22 that introduces air other than water from the outside. The first input port 21 is formed with a female thread 21a to which a water supply piping member (not shown) is connected. As shown in Figures 1 and 2, an air suction pipe 23 is connected to the second input port 22.

The fluid path forming member 30 is fixed to the member mounting portion 11 at a position downstream of the input port member 20. The fluid path forming member 30 has a spiral nozzle hole 31 through which water flows in from the first input port 21 and a straight hole 32 through which air flows in from the second input port 22. The fluid path forming member 30 is subjected to a pressing force due to movement when the input port member 20 is fastened to the member mounting portion 11 by the male and female screws, and is fixed in a sandwiched state between the input port member 20 and the member mounting portion 11.

Next, with reference to Figures 5 to 12, the detailed configuration of each component (main body member 10, input port member 20, fluid path forming member 30) that constitutes the fluid mixing device 1A will be described.

As shown in Figure 5, the main body member 10 has a component mounting section 11, a fluid mixing section 12, a diffuser section 13, and a straight pipe section 14 on the main body central axis CL. The outer periphery of the outlet side of the main body member 10 is formed with a male thread section 15 for mounting a shower head, high-pressure cleaning head, or microbubble generating head (not shown).

The member attachment portion 11 is a main body hole into which the input port member 20 and fluid path forming member 30 are attached. The member attachment portion 11 has a female thread portion 11a, a cylindrical inner surface portion 11b, a tapered inner surface portion 11c, and a stepped mating surface portion 11d. The input port member 20 and fluid path forming member 30 are attached by inserting and assembling the fluid path forming member 30 into the cylindrical inner surface portion 11b, the tapered inner surface portion 11c, and the stepped mating surface portion 11d, and then screwing the input port member 20 into the female thread portion 11a.

The fluid mixing section 12 is a flow path that mixes and agitates the water ejected by the swirling flow from the fluid path forming member 30 with the air sucked into the center of the swirling flow. The fluid mixing section 12 has a tapered inner surface 12a that gradually reduces from the inlet side inner diameter Din from the fluid path forming member 30 to the outlet side inner diameter Dout to the diffuser section 13.

The inlet-side inner diameter Din is the inner diameter at the position where it contacts the component mounting portion 11, and is set to an inner diameter larger than the circumscribing circle of the multiple first outlets 31b (described below). The outlet-side inner diameter Dout is the inner diameter at the position where it contacts the diffuser portion 13, and is set to the minimum inner diameter that provides at least the total cross-sectional area of the multiple first outlets 31b (described below). The outlet-side inner diameter Dout is set to a diameter smaller than the inlet-side inner diameter Din, and is set to the maximum inner diameter when reduced to obtain a flow velocity that ensures at least the minimum flow rate allowable for the device. Therefore, the outlet-side inner diameter Dout is appropriately determined depending on, for example, the inlet-side inner diameter Din, the biaxial inclination angle of the first outlets 31b, the axial length 300 of the fluid mixing portion 12, etc.

The axial length 300 of the fluid mixing section 12 is set to a length that allows the water ejected by the combined swirling flow to be mixed with the air drawn into the center of the swirling flow due to negative pressure, thereby stirring the mixture. The specific axial length 300 of the fluid mixing section 12 is set to a different length for each combination of fluids to be mixed, depending on the type and viscosity of the fluid. For example, once a combination of fluids to be mixed is selected, a comparative experiment of mixing and stirring performance is conducted by changing the axial length, and the length that achieves high mixing and stirring performance is determined. Here, the fluid inlet region of the fluid mixing section 12 where the water and air converge is provided with a first water outlet 31b and a second air outlet 32b formed on the tip surface 36a of the fluid path forming member 30 (described below) (see Figure 13).

The diffuser section 13 is a flow path that converts the kinetic energy of the mixed fluid flowing in from the fluid mixing section 12 into pressure energy and generates a backflow in the mixed fluid, stirring it and breaking down the air mixed with the water into air bubbles. The diffuser section 13 has an expanding tapered inner surface 13a, where the inner diameter on the inlet side of the diffuser (=outlet side inner diameter Dout), into which the mixed fluid flows from the fluid mixing section 12, expands toward the straight pipe section 14 on the outlet side of the mixed fluid.

Here, the taper angle of the expanding tapered inner surface 13a of the diffuser section 13 is set to an angle that can reduce the flow rate of the mixed flow from the fluid mixing section 12 and promote the occurrence of backflow. In Example 1, the taper angle of the expanding tapered inner surface 13a of the diffuser section 13 is set to an angle greater than the taper angle of the reducing tapered inner surface 12a. However, if the rate of increase in the flow path area (= the taper angle of the expanding tapered inner surface 13a) becomes too large, flow path loss increases. For this reason, the taper angle of the expanding tapered inner surface 13a is set to an angle that promotes the occurrence of backflow while suppressing an increase in flow path loss.

As shown in Figure 6, the input port member 20 has a first input port 21, a second input port 22, a connecting support portion 24, a first fluid hole 25, a second fluid path 26, an outer peripheral protrusion 27, and an axial center protrusion 28.

The first input port 21 is an axial port for directing water into the input side outer peripheral region of the fluid path forming member 30. The inner surface of the first input port 21 is formed with a female thread 21a to which a water supply piping member (not shown) or the like can be connected.

The second input port 22 is a radial port for guiding air to the axial center of the fluid path forming member 30. An air suction pipe 23 is connected to the inner surface of the second input port 22 (see Figures 1 and 2). Note that instead of the air suction pipe 23, a bleeder plug or the like that draws in outside air may be provided in the second input port 22. It is also possible to configure the system without the air suction pipe 23.

The connecting strut 24 is a component that connects the first input ports 21 at their intermediate positions in the diametric direction, and distributes the water from the first input port 21 and the air from the second input port 22, leading them to the fluid path forming member 30.

The first fluid hole 25 is formed in the connecting support portion 24 and is a flow path that divides water guided axially from the first input port 21 into two directions and guides it to the input-side outer peripheral region of the fluid path forming member 30. The first fluid hole 25 is composed of a pair of arc-shaped holes 25a, 25b divided into two by the connecting support portion 24 (see Figures 2 and 3). A water storage area is formed between the opening end surfaces 25c of the pair of arc-shaped holes 25a, 25b and the stepped surface 34a of the fluid path forming member 30 (described later) to prepare for the supply of water to the fluid path forming member 30 (see Figures 3 and 4).

The second fluid path 26 is formed in the connecting support 24 and is a flow path that guides air from the second input port 22 to the axial center of the fluid path forming member 30. The second fluid path 26 is composed of a radial flow path 26a and an axial flow path 26b. One end of the radial flow path 26a is connected to the second input port 22, and the other end is open to the center position of the connecting support 24. One end of the axial flow path 26b is connected to the radial flow path 26a, and the other end is open to the tip surface 28a of the axial protrusion 28. Note that while Figure 6 shows the radial flow path 26a configured to allow air to flow in only from above, it may also be configured to allow air to flow in from multiple directions, such as both above and below, or three equiangular directions. Furthermore, when radial flow paths that introduce fluid from multiple directions are provided, different types of fluid may be used in each radial flow path. However, when using different types of fluids, it is preferable to select fluids with similar viscosities, such as when one fluid is air and the other is also a gas.

The outer peripheral protrusion 27 is an annular protrusion that protrudes in an annular shape from the outer periphery of the main body member side end face of the input port member 20 and screws the input port member 20 to the member mounting portion 11 of the main body member 10. A male thread 27a is formed on the outer periphery of the outer peripheral protrusion 27, and is screwed into the female thread 11a of the member mounting portion 11. In Example 1, a seal that prevents water leakage is ensured by the elastic deformation of the material due to the pressure applied to the screw fixing portion between the male thread 27a and the female thread 11a. Note that if the screw fixing portion cannot prevent water leakage, a seal member may be provided at the screw fixing portion.

The axial projection 28 protrudes cylindrically from the center of the main body member-side end face of the input port member 20, and is a projection that connects the axial flow path 26b with the straight hole 32 formed in the fluid path-forming member 30 (see Figures 3 and 4). The tip surface 28a of the axial projection 28 protruding toward the main body member is pressed against the rear end surface 33a (see Figure 8) of the axial cylindrical portion 33 of the fluid path-forming member 30. In Example 1, the pressure applied to the tip surface 28a and rear end surface 33a causes elastic deformation of the material, ensuring a seal that prevents air leakage. Note that if air leakage cannot be prevented by the pressure between the tip surface 28a and rear end surface 33a, a seal member may be provided on the pressed surface.

As shown in Figures 7 to 9, the fluid path forming member 30 has a spiral nozzle hole 31 (nozzle hole), a straight hole 32, an axial cylindrical portion 33, a cylindrical portion 34, a tapered conical portion 35, and a stepped cylindrical portion 36. The external shape of the fluid path forming member 30 excluding the spiral nozzle hole 31 and straight hole 32 is formed in a bridge shape, integrally comprising the axial cylindrical portion 33, the cylindrical portion 34, the tapered conical portion 35, and the stepped cylindrical portion 36, as shown in Figures 7 and 8.

The axial cylindrical portion 33 corresponds to the axial protrusion 28 of the input port member 20 described above, and the leading end surface 28a of the axial protrusion 28 is pressed against the rear end surface 33a. The outer diameter of the rear end surface 33a of the axial cylindrical portion 33 is larger than the outer diameter of the leading end surface 28a of the axial protrusion 28, connecting the axial flow path 26b and the straight hole 32 to each other.

The cylindrical portion 34 has an outer peripheral surface with an outer diameter that corresponds to the cylindrical inner surface portion 11b of the component mounting portion 11. The tapered conical portion 35 has a tapered conical surface that corresponds to the tapered inner surface portion 11c of the component mounting portion 11. The stepped cylindrical portion 36 has an outer peripheral surface with an outer diameter that corresponds to the stepped mating surface portion 11d of the component mounting portion 11 (see Figure 5). In this way, the fluid path forming member 30, whose shape corresponds to the shape of the component mounting portion 11 of the main body member 10, can be assembled by inserting the fluid path forming member 30 into the main body member 10 in the axial direction. The configurations of the spiral nozzle hole 31 and straight hole 32 formed in the fluid path forming member 30 are described below.

The fluid path forming member 30 has a first water outlet 31b formed by the spiral nozzle hole 31 and a second air outlet 32b formed by the straight hole 32 formed on its tip surface 36a. The tip surface 36a of the fluid path forming member 30 is positioned so as to face the fluid inlet region of the fluid mixing section 12.

The spiral nozzle hole 31 is a nozzle hole that creates a compound swirling flow while accelerating the water supplied by a predetermined water pressure. The spiral nozzle hole 31 has a first inlet 31a formed in the step surface 34a between the axial column portion 33 and the cylindrical portion 34, and a first outlet 31b formed in the tip surface 36a of the stepped cylindrical portion 36. Here, the term "compound swirling flow" refers to a swirling flow that is a compound combination of an "overall swirling flow" and an "individual swirling flow." Overall swirling flow and individual swirling flow will be described later.

Six spiral nozzle holes 31 are formed. Each hole is arranged in a tapered cone shape. Each spiral nozzle hole 31 connects the first water inlet 31a and first water outlet 31b via a biaxially inclined hole, with the hole center axis HC inclined radially and circumferentially relative to the main body center axis CL. Therefore, when six water flows are accelerated and ejected from the first outlets 31b of the six spiral nozzle holes 31 in the biaxially inclined direction, an overall swirling flow is created by the six twisted water flows, whose intersections of the two inclined axes do not coincide with each other. "Twisted water flow" refers to the water flow in which water ejected from the first outlets 31b of the spiral nozzle holes 31 traces a spiral flowline that moves along the tapered inner surface 12a of the fluid mixing section 12.

Here, "inclined radially" refers to the hole center axis HC of the spiral nozzle hole 31 having a first inclination angle θ1 relative to the body center axis CL, where the hole center axis HC approaches the body center axis CL as it moves from the first inlet 31a to the first outlet 31b, as shown in Figure 8. Also, "inclined circumferentially" refers to the hole center axis HC of the spiral nozzle hole 31 having a second inclination angle θ2 relative to the body center axis CL, where the hole center axis HC moves away from the first inlet 31a to the first outlet 31b. In other words, the second inclination angle θ2 is expressed as the circumferential angle between a first radial line R1 connecting the body center axis CL and the center of the first inlet 31a, and a second radial line R2 connecting the body center axis CL and the center of the first outlet 31b, as shown in Figure 9. In Example 1, the first tilt angle θ1 and the second tilt angle θ2 are both set to the same tilt angle of 15°. The hole center axis HC shown in Figure 9 represents the biaxial tilt state in the radial direction (inner radial direction in Figure 9) and circumferential direction (clockwise circumferential direction in Figure 9) when the spiral nozzle hole 31 is viewed from the axial direction.

The spiral nozzle hole 31 has inner surface protrusions 31c that protrude spirally from the first water inlet 31a toward the first water outlet 31b on the inner surface of the nozzle hole, which is inclined on two axes. In Example 1, three inner surface protrusions 31c are formed on the inner surface of the spiral nozzle hole 31, protruding in a mountain shape at 120° intervals. Therefore, as water moves spirally through the spiral nozzle hole 31 with the inner surface protrusions 31c formed thereon while accelerating, individual swirling flows are created in each of the six spiral nozzle holes 31.

The detailed hole shape of the spiral nozzle hole 31 will be explained with reference to Figures 10 to 13. Hereinafter, as shown in Figure 10, the pin shape when a pin of the same shape is inserted into the spiral nozzle hole 31 (the inverted shape of the spiral nozzle hole 31) will be referred to as the spiral nozzle hole shape 31'.

As shown in Figure 11, the spiral nozzle hole shape 31' is divided into a first section S1 extending from the first inlet 31a to a midpoint, and a second section S2 extending from the midpoint to the first outlet 31b. A connecting section S3 is set between the first section S1 and the second section S2. The first section S1 is the longest section, accounting for approximately 80% of the total. The length relationship between the sections is first section S1 > second section S2 > connecting section S3.

The first section S1 is an inner protrusion section with inner protrusions 31c on the inner surface of the tapered hole of the spiral nozzle hole 31. The inner protrusions 31c are represented by recessed grooves in the spiral nozzle hole shape 31'. The second section S2 is a cylindrical section with an equal-diameter hole rather than a tapered hole. The connecting section S3 is a conical section smoothly connecting the inner protrusion section and the equal-diameter hole section. The tip surfaces 36a of the six first outlets 31b are inclined tip surfaces perpendicular to the hole center axis HC. Therefore, the tip surface shape of the first outlets 31b is not a flat surface perpendicular to the main body center axis CL. In other words, the tip surface shape of the first outlets 31b is an uneven inclined surface with a stepped surface and a fan-shaped inclined surface repeated six times in the circumferential direction, as shown in Figure 13.

The opening shape of the first inlet 31a of the spiral nozzle hole 31 is elliptical when the three inner surface protrusions 31c are removed (see the dashed line in Figure 9 showing the spiral nozzle hole 31 when the three inner surface protrusions 31c are removed). On the other hand, the opening shape of the first outlet 31b of the spiral nozzle hole 31 is circular, as is clear from the tip surface shape of the spiral nozzle hole shape 31' in Figure 12. The term "circular shape" refers to a curved shape formed by a set of points equidistant from a fixed point (center point), and is used to clearly distinguish it from an elliptical shape. Note that a "circular shape" does not necessarily require a high degree of circularity, and includes circular shapes created by resin molding, for example.

The detailed shape of the straight hole 32 will be explained with reference to Figures 8 and 13. The straight hole 32 is a hole that uses negative pressure to guide air from the outside toward the center surrounded by multiple first outlets 31b at the tip surface 36a of the fluid path forming member 30. The straight hole 32 is formed by connecting the second air inlet 32a and second outlet 32b with an axial hole. Here, the axial hole refers to a hole whose hole center axis AC is aligned with the main body center axis CL.

The straight hole 32 has a buffer hole 37 at the position of the second outlet 32b, which has an inner diameter larger than the inner diameter of the straight hole 32 (see Figure 13). The buffer hole 37 is provided to slow down and adjust the flow rate of air drawn in due to the generation of negative pressure, and the inner diameter and length of the buffer hole 37 are set according to the selected fluid. In particular, the viscosity of the selected fluid plays a major role in the flow rate due to negative pressure drawing. For example, for fluids with low viscosity such as air, whose flow rate increases due to negative pressure drawing, the inner diameter and length of the buffer hole 37 are set to slow down the flow to match the water ejection speed caused by the swirling flow. Conversely, for fluids with high viscosity that do not increase the flow rate due to negative pressure drawing, the buffer hole 37 may be made smaller in volume, or the buffer hole 37 may be eliminated entirely.

Next, we will explain the gas-liquid multiphase fluid generation action of mixing water W and air A to generate gas-liquid multiphase fluid M, with reference to the analysis example in Figures 14 to 16. Here, as an analysis example, we will show an example that shows velocity vectors (Figure 14), streamlines of water and air (Figure 15), and streamlines of air only (Figure 16) when analytical conditions are given for mixing water (water pressure = 0.1 MPa) and air (atmospheric pressure = 0 MPa) to generate a gas-liquid multiphase fluid.

When water W flows into the first input port 21 of the input port member 20 under a predetermined water pressure (0.1 MPa), it passes through the first fluid hole 25, which is a pair of arc-shaped holes 25a, 25b (see Figures 2 and 3), and reaches the first inlet 31a of the spiral nozzle hole 31 formed in the fluid path forming member 30. In the fluid path forming member 30, the water W reaches the first inlet 31a of the spiral nozzle hole 31 formed by the nozzle hole (see Figure 8) and moves toward the first outlet 31b while accelerating, and individual swirling flows are created by the inner surface protrusions 31c formed on the inner surface of the spiral nozzle hole 31. When the water W flows out of the first outlet 31b of the six spiral nozzle holes 31, an overall swirling flow is created by six bundles of twisted water flows due to the biaxially inclined configuration of the six spiral nozzle holes 31.

As a result, an accelerated combined swirling flow (total swirling flow + individual swirling flow) is ejected from the first outlets 31b for water W on the tip surface 36a of the fluid path forming member 30 toward the fluid inlet region of the fluid mixing section 12. Therefore, the conical region surrounded by the tip surface 36a of the fluid path forming member 30 and the inner surfaces of the combined swirling flows ejected from the six first outlets 31b becomes the primary negative pressure generation region 100 where negative pressure is generated by the Venturi effect, as shown in Figure 14. The "Venturi effect" is an effect of fluid mechanics, and refers to the phenomenon whereby narrowing the cross-sectional area of a fluid flow and increasing the flow velocity creates low-pressure or negative-pressure areas.

The primary negative pressure generation region 100 formed in the central portion of the tip surface 36a of the fluid path forming member 30 coincides with the position of the second outlet 32b of the straight hole 32 through which air A flows. Therefore, air A present in air passages such as the straight hole 32 of the fluid path forming member 30 is subjected to a negative pressure drawing force corresponding to the differential pressure between atmospheric pressure and negative pressure. Therefore, external air A is drawn into the inner center of the water W from the second input port 22 of the input port member 20 via the radial flow paths 26a, axial flow paths 26b, the straight hole 32, and the buffer hole 37. Here, the inner center of the water W into which air A is drawn refers to the apex region of the tapered cone when six streams of water W are ejected from the six spiral nozzle holes 31 in a tapered cone shape.

As a result, the confluence of the water W and air A becomes an inward suction confluence, in which air A is sucked toward the center of the inside of the water W. The area where the water W and air A begin to confluence is the fluid inlet area of the fluid mixing section 12, where the tip surface 36a of the fluid path forming member 30 is located. As a result, in the fluid mixing section 12, air A is efficiently drawn into the water W being sprayed out by the combined swirling flow, and mixing and stirring of the water W and air A begins.

When water W passes through the fluid mixing section 12 toward the fluid outlet, it swirls and increases its speed toward the diffuser section 13, as shown in the streamline characteristics of Figure 15. As shown in the streamline characteristics of air A in Figure 16, air A flows swirlingly through the center of the inner periphery of the water W due to the combined swirling flow, and is efficiently drawn into the swirling water W and mixed and stirred. Furthermore, since the fluid mixing section 12 has a tapered inner surface 12a, the water W due to the combined swirling flow passes toward the outlet while increasing in speed. Therefore, as shown in Figure 14, a secondary negative pressure generation region 200 is formed by the Venturi effect in the outer periphery of the boundary between the fluid mixing section 12 and the diffuser section 13.

Next, the mixed fluid of water W and air A that leaves the fluid mixing section 12 flows into the diffuser section 13, where the kinetic energy of the mixed fluid flowing in from the fluid mixing section 12 is converted into pressure energy, causing the flow velocity to decrease. Therefore, in the diffuser section 13 and straight pipe section 14, backflows and vortex flows are generated in the mixed fluid, as shown by the velocity vectors (arrows) in Figure 13. These backflows and vortex flows cause the mixed fluids to collide with each other, creating a stirring effect. This stirring effect breaks down the band-like air masses mixed into the water W and breaks them down into air bubbles, resulting in the generation of a gas-liquid multiphase fluid M with countless air bubbles scattered throughout the water W.

As described above, the fluid mixing device 1A of Example 1 provides the following effects.

(1) A fluid mixing device 1A for mixing multiple fluids comprises a main body member 10, an input port member 20, and a fluid path forming member 30. The main body member 10 has a member mounting portion 11 and a fluid mixing portion 12 on the main body central axis CL along the flow direction of the multiple fluids. The input port member 20 is fixed to the member mounting portion 11 and has a first input port 21 for introducing a first fluid (water W) from the outside and a second input port 22 for introducing a second fluid (air A) different from the first fluid from the outside. The fluid path forming member 30 is fixed downstream of the input port member 20 and has a nozzle hole (spiral nozzle hole 31) through which the first fluid flows from the first input port 21 and a straight hole 32 through which the second fluid flows from the second input port 22. The nozzle hole (spiral nozzle hole 31) is formed by a plurality of holes arranged in a tapered cone shape, connecting a first inlet 31a and a first outlet 31b for the first fluid with a biaxially inclined hole whose hole center axis HC is inclined radially and circumferentially with respect to the body center axis CL. The straight hole 32 is formed by connecting a second inlet 32a and a second outlet 32b for the second fluid with an axial hole whose hole center axis AC is aligned with the body center axis CL. The fluid path forming member 30 has a tip surface 36a formed with a plurality of first outlets 31b opened circumferentially and a second outlet 32b opened at the center surrounded by the plurality of first outlets 31b. The tip surface 36a of the fluid path forming member 30 is positioned in the fluid inlet region of the fluid mixing section 12. Therefore, when mixing multiple fluids (water W, air A) to generate a mixed fluid (gas-liquid multiphase fluid M), a fluid mixing device 1A can be provided that has improved mixing and stirring performance for multiple fluids.

(2) The nozzle hole is a spiral nozzle hole 31 having an inner surface inclined on two axes, with inner surface protrusions 31c that protrude spirally from the first inlet 31a for the first fluid (water W) toward the first outlet 31b. Therefore, the swirling flow ejected from the first outlet 31b of the spiral nozzle hole 31 is a compound swirling flow that combines the overall swirling flow created by the biaxially inclined nozzle hole with the individual swirling flows created by the inner surface protrusions 31c. This allows for quick initiation of mixing of the first fluid (water W) and the second fluid (air A) in the fluid inlet region of the fluid mixing section 12, and improves the mixing and stirring performance of the first fluid (water W) and the second fluid (air A) in the fluid mixing section 12. Additionally, improved mixing and stirring performance in the fluid mixing section 12 allows for a shorter axial length 300 of the fluid mixing section 12, contributing to a more compact fluid mixing device 1A.

(3) The spiral nozzle hole 31 is divided into a first section S1 extending from the first inlet 31a to a midpoint, and a second section S2 extending from the midpoint to the first outlet 31b. The first section S1 is an inner surface protrusion section having an inner surface protrusion 31c on the inner surface of the nozzle hole, and the second section S2 is a uniform diameter section having uniform diameter holes. The tip surface 36a of the first outlet 31b is an inclined surface perpendicular to the hole center axis HC. Therefore, the hole connecting to the first outlet 31b is a uniform diameter hole, and the opening shape of the spiral nozzle hole 31 at the first outlet 31b for the first fluid (water W) is a perfect circle rather than an ellipse. This reduces the disruption of the flow line of the first fluid (water W) ejected from the circular first outlet 31b of the spiral nozzle hole 31 compared to when the first fluid is ejected from an elliptical outlet.

(4) The fluid path forming member 30 has a buffer hole 37 with an inner diameter larger than that of the straight hole 32 at the position of the second outlet 32b, which opens in the center surrounded by the first outlet 31b for the first fluid (water W). Therefore, the flow velocity of the second fluid (air A) toward the fluid inlet region of the fluid mixing section 12 due to negative pressure suction is slowed by the buffer hole 37, whose flow path cross-sectional area is larger than that of the straight hole 32. Therefore, the flow velocity of the second fluid (air A) sucked toward the inner center of the combined swirling flow can be adjusted to match the flow velocity of the combined swirling flow of the first fluid (water W). Therefore, in the fluid inlet region of the fluid mixing section 12, the second fluid (air A) merges at an appropriate speed toward the inner center of the combined swirling flow of the first fluid (water W), improving the merging performance of the first fluid (water W) and the second fluid (air A).

(5) The fluid mixing section 12 has a tapered inner surface 12a that reduces the inlet inner diameter Din of the fluids (water W, air A) flowing in from the fluid path forming member 30 to the outlet inner diameter Dout. Here, negative pressure is generated in the fluid inlet region of the fluid mixing section 12. For this reason, if the fluid mixing section had an inner surface without a taper, the mixed fluid could be drawn toward the fluid inlet side by the negative pressure, causing it to slow down or stagnate. In contrast, the fluid mixing section 12 has a tapered inner surface 12a that promotes acceleration, thereby ensuring the movement of the mixed fluid at a predetermined flow rate. This prevents the mixed fluid passing through the fluid mixing section 12 from slowing down or stagnation, further improving the mixing and stirring performance of the first fluid (water W) and the second fluid (air A).

(6) The fluid mixing unit 12 sets the minimum inner diameter of the outflow side inner diameter Dout to an inner diameter that provides the total cross-sectional area of at least the multiple first outflow ports 31b. Therefore, by setting the minimum inner diameter of the outflow side inner diameter Dout to an inner diameter that provides the total cross-sectional area of the multiple first outflow ports 31b, an increase in flow path resistance due to excessive narrowing can be suppressed. Therefore, in the fluid mixing unit 12, an increase in flow path resistance due to excessive narrowing of the outflow side inner diameter Dout can be suppressed. Furthermore, by setting the maximum inner diameter of the outflow side inner diameter Dout to an inner diameter that provides a flow velocity that ensures at least the minimum flow rate allowable as the device flow rate, a decrease in flow velocity due to excessive opening of the outflow side inner diameter Dout can be suppressed.

(7) The main body member 10 has a diffuser section 13 located downstream and adjacent to the fluid mixing section 12. The diffuser section 13 has an expanding tapered inner surface 13a, which expands the inner diameter of the diffuser inlet side, into which the mixed fluid flows from the fluid mixing section 12, toward the mixed fluid outlet side. Therefore, in the diffuser section 13 with the expanding tapered inner surface 13a, the kinetic energy of the mixed fluid flowing in from the fluid mixing section 12 is converted into pressure energy, reducing the flow rate and generating backflow and vortex flow in the mixed fluid. Therefore, in the diffuser section 13, the generated backflow and vortex flow effectively agitate the mixed fluid, thereby generating a mixed fluid (gas-liquid multiphase fluid M) in which minute particles of the second fluid (air A) are dispersed throughout the first fluid (water W).

While Example 1 is an apparatus that mixes two types of fluids, Example 2 is an example of an apparatus that can mix three types of fluids by adding one more type of fluid in addition to the two types of fluids.

Referring to Figures 17 and 18, the configuration of a fluid mixing device 1B according to a second embodiment will be described. This device mixes an additive liquid (third fluid) with a gas-liquid multiphase fluid, which is a mixture of water (first fluid) supplied at a predetermined hydraulic pressure and air (second fluid), to produce a three-component mixed fluid. Here, the additive liquid may be, for example, a cleaning liquid selected for each application.

As shown in Figures 17 and 18, the fluid mixing device 1B comprises a main body member 10, an input port member 20, and a fluid path forming member 30.

The main body member 10 is a cylindrical member that has a component mounting section 11, a fluid mixing section 12, a diffuser section 13, and a straight pipe section 14 on the main body central axis CL along the flow direction of water and air (flow direction from left to right in Figure 17).

The fluid mixing section 12 has a convergent tapered inner surface 12a, as in Example 1. The diffuser section 13 is positioned adjacent to and downstream of the fluid mixing section 12 and has an divergent tapered inner surface 13a.

A third input port 16 and radial flow paths 17 are provided at the boundary between the fluid mixing section 12 and the diffuser section 13, which introduce the additive liquid agent radially from the outside. One end of the radial flow path 17 is connected to the third input port 16, and the other end opens at the boundary between the fluid mixing section 12 and the diffuser section 13. An additive liquid agent suction pipe 18 is connected to the third input port 16. The other components are the same as those of the fluid mixing device 1A of Example 1, so detailed description will be omitted.

Next, we will explain the triple-phase fluid generation process, in which an additive liquid is added to a gas-liquid multiphase fluid, which is a mixture of water and air, to generate a triple-phase fluid.

First, in the fluid mixing section 12 having a tapered inner surface 12a, water passes through the combined swirling flow from the inlet side to the outlet side while increasing in speed. Therefore, as explained in the first embodiment above, a secondary negative pressure generation region 200 (see Figure 14) is formed in the outer peripheral boundary region between the fluid mixing section 12 and the diffuser section 13. Therefore, focusing on the secondary negative pressure generation region 200, holes (third input port 16 and radial flow path 17) perpendicular to the main body central axis CL are drilled toward the secondary negative pressure generation region 200, providing a suction flow path for the additive liquid agent; this is the fluid mixing device 1B of the second embodiment.

As a result, the additive liquid agent sucked in by negative pressure suction via the additive liquid agent suction pipe 18, the third input port 16, and the radial flow path 17 is introduced perpendicular to the water caused by the combined swirling flow. As a result, the additive liquid agent mixes with the water while tearing the water apart in the shear direction caused by the combined swirling flow. The swirling water increases the mixing and stirring effect of the additive liquid agent, generating a three-component fluid mixture by mixing the additive liquid agent with the gas-liquid multiphase fluid M, which is a mixture of water and air. The gas-liquid multiphase fluid generation process by which water and air are mixed to generate the gas-liquid multiphase fluid M is similar to that of the fluid mixing device 1A of the first embodiment, and therefore will not be described here.

As described above, the fluid mixing device 1B of Example 2 provides the following advantages in addition to the advantages of Example 1.

(8) The fluid mixing section 12 has a tapered inner surface 12a that gradually narrows from an inlet inner diameter Din, through which fluid from the fluid path-forming member 30 flows, to an outlet inner diameter Dout. The main body member 10 has a diffuser section 13 located downstream adjacent to the fluid mixing section 12. At the boundary between the fluid mixing section 12 and the diffuser section 13, there is a third input port 16 and a radial flow path 17 that introduce a third fluid (additive liquid agent) radially from the outside. That is, the fluid mixing section 12, which has a tapered inner surface 12a, generates a secondary negative pressure at the outlet side of the fluid mixing section 12. Therefore, when the third input port 16 and the radial flow path 17 are provided perpendicular to the main body central axis CL with respect to the secondary negative pressure generation region 200, the third fluid (additive liquid agent) is subjected to a drawing force due to the secondary negative pressure and is introduced perpendicular to the first fluid (water) due to the combined swirling flow. Therefore, by simply adding a simple flow path configuration that utilizes the generation of secondary negative pressure, it is possible to generate a three-component mixed fluid by mixing a first fluid (water) with a second fluid (air) and then further mixing it with a third fluid (additive liquid).

The fluid mixing device of the present invention has been described above based on Examples 1 and 2, but the specific configuration is not limited to these examples. Design changes and additions are permitted as long as they do not deviate from the gist of the invention as defined in each claim.

In Examples 1 and 2, an example was shown in which six holes were arranged in a tapered cone shape as the spiral nozzle holes 31. However, the spiral nozzle holes are not limited to six holes, and may be, for example, an example in which three or more holes are arranged in a tapered cone shape.

In Examples 1 and 2, the nozzle hole is a biaxially inclined hole, and a spiral nozzle hole 31 is used, which has inner protrusions 31c that protrude helically from the inner surface of the nozzle hole, providing a preferred example in which individual swirling flows are added to the overall swirling flow to form a compound swirling flow. However, the nozzle hole may also be a biaxially inclined nozzle hole without inner protrusions, and an overall swirling flow may be created by the biaxially inclined nozzle hole. Furthermore, when the nozzle hole has inner protrusions that protrude helically from the inner surface, Example 1 illustrates an example with three inner protrusions, but this is not limited to three, and at least one inner protrusion may be used. In Example 1, an example is shown in which the cross-sectional shape of the inner protrusions is mountain-shaped, but the cross-sectional shape of the inner protrusions is not limited to a mountain-shaped shape, and any shape that can create individual swirling flows may be used.

In Examples 1 and 2, when forming a spiral nozzle hole 31 with a biaxial tilt, the first axial tilt angle θ1 and the second circumferential tilt angle θ2 are set to the same tilt angle of 15°. However, when forming a spiral nozzle hole with a biaxial tilt, the first axial tilt angle θ1 and the second circumferential tilt angle θ2 are not limited to being set to the same tilt angle, and it is of course also possible to set the first axial tilt angle θ1 and the second circumferential tilt angle θ2 to different angles.

In Examples 1 and 2, when forming a spiral nozzle hole 31 with a biaxial tilt, the tip surface 36a of the first outlet 31b of the first fluid is an inclined surface perpendicular to the hole center axis HC, and the opening shape of the spiral nozzle hole 31 at the first outlet 31b is a perfect circle. However, when forming a spiral nozzle hole with a biaxial tilt, if a first fluid is selected for which disruption of the streamline ejected from the first outlet is not a problem, the fluid may be ejected from an elliptical outlet.

In Examples 1 and 2, an example was shown in which a buffer hole 37 with an inner diameter larger than the inner diameter of the straight hole 32 formed in the fluid path forming member 30 is provided at the position of the second outlet 32b of the straight hole 32. However, if a fluid with a high viscosity is selected as the second fluid, the fluid path forming member may not have a buffer hole. Furthermore, in an example in which a buffer hole is provided, the inner diameter or length of the hole may be different from that of Example 1.

In Examples 1 and 2, the fluid mixing section 12 has a tapered inner surface 12a along the entire axial length 300, and the outlet inner diameter Dout is set smaller than the inlet inner diameter Din. However, the fluid mixing section may have a tapered inner surface along at least a portion of the entire axial length. For example, the tapered inner surface may be a tapered inner surface from the start position to an intermediate position, and the remaining portion may be a constant diameter inner surface. Alternatively, the entire axial length may be a constant diameter inner surface from the start position to an intermediate position, and the remaining portion may be a tapered inner surface. Furthermore, the entire axial length may be a constant diameter inner surface in the front and rear regions, and the intermediate region may be a tapered inner surface in the rear and the middle region.

In Examples 1 and 2, an example was shown in which a diffuser section 13 having an enlarged tapered inner surface 13a was placed downstream adjacent to the fluid mixing section 12. However, an example may also be shown in which a straight pipe section whose inner diameter suddenly expands from the inner diameter on the outlet side of the fluid mixing section is placed downstream adjacent to the fluid mixing section.

In Example 2, an example was shown in which the multiple fluids to be mixed were water as the first fluid, air as the second fluid, and an additive liquid agent, and a three-component mixed fluid was generated by mixing the water and air mixture with the additive liquid agent. However, the first and second fluids are not limited to the above example combination of water and air. Furthermore, the third fluid is not limited to the additive liquid agent (liquid), and may be another liquid or gas.

1A Fluid mixing device 10 Main body member 11 Component mounting portion 12 Fluid mixing portion 12a Converging tapered inner surface 13 Diffuser portion 13a Expanding tapered inner surface 20 Input port member 21 First input port 22 Second input port 30 Fluid path forming member 31 Spiral nozzle hole (nozzle hole)
31a First inlet 31b First outlet 31c Inner surface protrusion 32 Straight hole 32a Second inlet 32b Second outlet 36a Tip surface 37 Buffer hole 1B Fluid mixing device 16 Third input port 17 Radial flow path CL Body central axis HC Hole central axis W Water (first fluid)
A. Air (second fluid)
M Gas-liquid multiphase fluid (mixed fluid)
S1: First section S2: Second section Din: Inlet side inner diameter of the fluid mixing section 12 Dout: Outlet side inner diameter of the fluid mixing section 12

Claims (8)

A fluid mixing device for mixing a plurality of fluids,
a main body member having a member mounting portion and a fluid mixing portion on a central axis of the main body along the flow direction of the plurality of fluids;
an input port member fixed to the member mounting portion, the input port member having a first input port for introducing a first fluid from the outside and a second input port for introducing a second fluid different from the first fluid from the outside;
a fluid path forming member fixed at a downstream position of the input port member, the fluid path forming member having a nozzle hole through which the first fluid from the first input port flows and a straight hole through which the second fluid from the second input port flows,
the nozzle hole is formed by arranging a plurality of holes in a tapered cone shape, and connecting a first inlet and a first outlet of the first fluid by a biaxially inclined hole whose hole central axis is inclined in a radial direction and a circumferential direction with respect to the main body central axis,
the straight hole is formed by connecting the second inlet and the second outlet for the second fluid by an axial hole whose hole central axis is aligned with the main body central axis,
the fluid path forming member has a tip end surface formed with the first outlets, which are opened in a plurality of locations on a circumference, and the second outlet, which is opened in a central portion surrounded by the plurality of first outlets, and the tip end surface is disposed in a fluid inlet region of the fluid mixing section;
the nozzle hole is a spiral nozzle hole having an inner surface inclined on two axes, the inner surface of the nozzle hole having an inner protrusion that protrudes spirally from the first inlet toward the first outlet of the first fluid. 2. The fluid mixing device according to claim 1,
The spiral nozzle hole divides a section from the first inlet to the first outlet of the first fluid into a first section from the first inlet to an intermediate position and a second section from the intermediate position to the first outlet,
the first section is an inner surface protrusion section having the inner surface protrusion on the inner surface of the nozzle hole, the second section is a same diameter hole section having a same diameter hole formed therein, and a tip surface of the first outlet is an inclined surface orthogonal to the central axis of the hole. The fluid mixing device according to claim 1 or 2,
The fluid mixing device according to claim 1, wherein the fluid path forming member has a buffer hole at the position of the second outlet, the buffer hole having an inner diameter larger than the inner diameter of the straight hole. 4. The fluid mixing device according to claim 1,
The fluid mixing device according to claim 1, wherein the fluid mixing section has a tapered inner surface that gradually reduces from an inflow side inner diameter into which the fluid from the fluid path forming member flows to an outflow side inner diameter. 5. The fluid mixing device according to claim 4,
The fluid mixing device according to claim 1, wherein the fluid mixing section sets the minimum inner diameter of the outlet side inner diameter to an inner diameter that provides a total cross-sectional area of at least a plurality of the first outlets. 6. The fluid mixing device according to claim 1,
the body member has a diffuser section located downstream adjacent the fluid mixing section;
the diffuser section has an expanding tapered inner surface in which the inner diameter of the diffuser inlet side, into which the mixed fluid flows from the fluid mixing section, expands toward the mixed fluid outlet side. 7. The fluid mixing device according to claim 1,
the fluid mixing portion has a tapered inner surface that gradually reduces from an inflow side inner diameter into which the fluid from the fluid path forming member flows to an outflow side inner diameter,
the body member has a diffuser section located downstream adjacent the fluid mixing section;
a third input port and a radial flow path for introducing a third fluid from the outside in a radial direction at a boundary between the fluid mixing section and the diffuser section. A fluid mixing device for mixing a plurality of fluids,
a main body member having a member mounting portion and a fluid mixing portion on a central axis of the main body along the flow direction of the plurality of fluids;
an input port member fixed to the member mounting portion, the input port member having a first input port for introducing a first fluid from the outside and a second input port for introducing a second fluid different from the first fluid from the outside;
a fluid path forming member fixed at a downstream position of the input port member, the fluid path forming member having a nozzle hole through which the first fluid from the first input port flows and a straight hole through which the second fluid from the second input port flows,
the nozzle hole is formed by arranging a plurality of holes in a tapered cone shape, and connecting a first inlet and a first outlet of the first fluid by a biaxially inclined hole whose hole central axis is inclined in a radial direction and a circumferential direction with respect to the main body central axis,
the straight hole is formed by connecting the second inlet and the second outlet for the second fluid by an axial hole whose hole central axis is aligned with the main body central axis,
the fluid path forming member has a tip end surface formed with the first outlets, which are opened in a plurality of locations on a circumference, and the second outlet, which is opened in a central portion surrounded by the plurality of first outlets, and the tip end surface is disposed in a fluid inlet region of the fluid mixing section;
a buffer hole having an inner diameter larger than the inner diameter of the straight hole at the position of the second outlet,