Gas-liquid separation device

Abstract

Provided is a gas-liquid separation device capable of capturing liquid at a position further downstream of a swirl flow generating member, regardless of the flow rate of gas-liquid two-phase fluid. The gas-liquid separation device (16) is provided with a pipe member (21) through which gas-liquid two-phase fluid flows, and a swirl flow generating member (22) disposed inside the pipe member (21), the gas-liquid two-phase fluid being caused to swirl by the swirl flow generating member (22) to separate gas and liquid, the swirl flow generating member (22) having a wing portion (32) extending in a spiral shape with the center axis (O1) of the pipe member (21) as the center, the front end (32a) in the radial direction of the pipe being continuous over the entire circumference of the pipe member (21) when the pipe member (21) is viewed in the axial direction. Furthermore, a communication portion (34) is provided between the pipe member (21) and the swirl flow generating member (22), the communication portion communicating a first space further upstream of the swirl flow generating member with a second space further downstream of the swirl flow generating member.

Description

TECHNICAL FIELD

[0001] The present application relates to a gas-liquid separation device that separates gas and liquid included in a gas-liquid two-phase fluid. BACKGROUND

[0002] Conventionally, a gas-liquid separation device is known that separates a gas-liquid two-phase fluid flowing in a pipe member into gas and liquid by a swirl flow generating member that swirls the gas-liquid two-phase fluid flowing in the pipe member (for example, refer to Patent Literature 1).

[0003] PRIOR ART DOCUMENTS

[0004] PATENT LITERATURE

[0005] Patent Literature 1: Japanese Patent Application Laid-Open No. 2010-104906 SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] However, in the conventional gas-liquid separation device, the swirl flow generating member has a wing portion that extends spirally around the center axis of the pipe member. Moreover, when the pipe member is viewed from the axial direction, the front end of the wing portion in the radial direction of the pipe member is continuous over the entire circumference of the pipe member, and a gap extending in the axial direction cannot be formed between adjacent wing portions. Further, the entire length of the wing portion is in contact with the inner circumferential surface of the pipe. When the gas-liquid two-phase fluid is flowing at a low flow rate, the liquid does not become fine particles, and is naturally separated from the gas before being swirled and becomes water droplets that adhere to the inner circumferential surface of the pipe. The liquid that has become water droplets flows along the pipe axis inside the pipe member by the flow of the gas, but the flow is hindered because the wing portion of the swirl flow generating member is in contact with the inner circumferential surface of the pipe. Therefore, a drain pipe needs to be provided at a position upstream of the swirl flow generating member in the flow direction of the gas-liquid two-phase fluid, and the water droplets are guided to a water storage tank before flowing into the arrangement region of the swirl flow generating member.

[0008] However, if the drain pipe is provided or the drain pipe is connected to the water storage tank, the degree of freedom in arranging the members is reduced, and this causes a problem of hindering cost reduction as a gas-liquid separation device.

[0009] The present application is achieved in view of the above-described problems, and aims to provide a gas-liquid separation device that can capture liquid at a position downstream of a swirl flow generating member without being affected by the flow rate of a gas-liquid two-phase fluid.

[0010] MEANS FOR SOLVING THE PROBLEMS

[0011] To achieve the above object, the gas-liquid separation device of the present application has a pipe member through which a gas-liquid two-phase fluid flows, and a swirl flow generating member disposed inside the pipe member, and separates the gas and the liquid by swirling the gas-liquid two-phase fluid with the swirl flow generating member. Here, the swirl flow generating member has a wing portion that extends spirally around the center axis of the pipe member, and the front end of the wing portion in the pipe radial direction is continuous over the entire circumference of the pipe member when the pipe member is viewed from the axial direction. Further, a communication portion is provided between the pipe member and the swirl flow generating member, and the communication portion communicates a first space upstream of the swirl flow generating member and a second space downstream of the swirl flow generating member.

[0012] Effects of the Invention

[0013] Thus, in the present application, even when the front end of the wing portion of the swirl flow generating member in the pipe radial direction is continuous over the entire circumference of the pipe member when the pipe member is viewed from the axial direction, the liquid can be trapped at a position further downstream of the swirl flow generating member than the swirl flow generating member, without being affected by the flow rate of the gas-liquid two-phase fluid. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 is a system diagram showing an exhaust gas recirculation system of an internal combustion engine to which the gas-liquid separation device of Example 1 is applied.

[0015] Figure 2 is a cross-sectional view showing the gas-liquid separation device of Example 1.

[0016] Figure 3A is a perspective view showing the swirl flow generating member of Example 1.

[0017] Figure 3B is a side view showing the swirl flow generating member of Example 1.

[0018] Figure 3C is a front view of the swirl flow generating member of Example 1 as viewed from the fluid inflow side.

[0019] Figure 4 is Figure 2 the A-A cross-sectional view shown.

[0020] Figure 5 is an explanatory diagram showing the flow of the gas-liquid two-phase fluid at a high flow rate in the gas-liquid separation device of Example 1.

[0021] Figure 6 is an explanatory diagram showing the flow of the gas-liquid two-phase fluid at a low flow rate in the gas-liquid separation device of Example 1.

[0022] Figure 7is an important part cross-sectional view showing a first modification example of the gas-liquid separation device of Embodiment 1.

[0023] Figure 8 is an important part cross-sectional view showing a second modification example of the gas-liquid separation device of Embodiment 1.

[0024] Figure 9 is an important part cross-sectional view showing a third modification example of the gas-liquid separation device of Embodiment 1. DETAILED DESCRIPTION

[0025] Hereinafter, based on Embodiment 1 shown in the drawings, the manner of the gas-liquid separation device for implementing the present application will be described.

[0026] (Embodiment 1)

[0027] First, the structure of the gas-liquid separation device in Embodiment 1 will be described by dividing it into "system overall structure of application example", "detailed structure of gas-liquid separation device", and "detailed structure of rotational flow generating member".

[0028] [System overall structure of application example]

[0029] Figure 1 is an overall system diagram showing an exhaust gas recirculation system S of an internal combustion engine 1 to which the gas-liquid separation device 16 of Embodiment 1 is applied. The gas-liquid separation device 16 of Embodiment 1 is applied to the exhaust gas recirculation system S of the internal combustion engine 1 shown in Figure 1 Herein, the internal combustion engine 1 shown in Figure 1 is a diesel engine mounted on a vehicle as a drive source for running, and has four cylinders (not shown). The respective cylinders are connected to an intake passage 2 and an exhaust passage 3, respectively.

[0030] The intake passage 2 is formed with an intake port 2a at an end portion, and an air cleaner 4 for filtering intake air, a compressor 5a of a turbocharger 5, an intercooler 6 for cooling intake air, and a throttle valve 7 for adjusting the amount of intake air are provided in this order from the intake port 2a side. In the exhaust passage 3, a turbine 5b of the turbocharger 5, an exhaust purification catalyst 8 for purifying exhaust gas, and an exhaust throttle valve 9 for adjusting the flow rate of exhaust gas are provided in this order from the internal combustion engine 1 side. Further, a muffler 10 is provided on the downstream side of the exhaust throttle valve 9, and an exhaust port 3a is formed at the front end thereof.

[0031] The intake passage 2 and the exhaust passage 3 are connected by a low-pressure EGR passage 11 and a high-pressure EGR passage 12. Herein, "EGR" means a technology (Exhaust Gas Recirculation) of taking out a part of burned exhaust gas in the internal combustion engine 1 and making it intake again, and is also called exhaust gas recirculation.

[0032] The low-pressure EGR passage 11 connects the intake passage 2 upstream of the compressor 5a and the exhaust passage 3 downstream of the exhaust purification catalyst 8. On the other hand, the high-pressure EGR passage 12 connects the intake passage 2 downstream of the compressor 5a and the exhaust passage 3 upstream of the turbine 5b. Thus, in the low-pressure EGR passage 11, exhaust gas that has passed through the turbine 5b is returned to the intake side of the compressor 5a. Also, in the high-pressure EGR passage 12, exhaust gas before flowing into the turbine 5b is returned to the intake side that has passed through the compressor 5a.

[0033] An EGR cooler 13 for cooling exhaust gas introduced into the intake passage 2 and a low-pressure EGR valve 14 for adjusting the flow rate of exhaust gas returned to the intake passage 2 via the low-pressure EGR passage 11 are provided in the low-pressure EGR passage 11. A high-pressure EGR valve 15 for adjusting the flow rate of exhaust gas returned to the intake passage 2 via the high-pressure EGR passage 12 is provided in the high-pressure EGR passage 12.

[0034] Here, in the low-pressure EGR passage 11, exhaust gas can be returned without reducing the turbine bypass flow rate of the turbocharger 5, and the NOx reduction effect is large. However, EGR gas can possibly generate condensed water by cooling in the EGR cooler 13 or mixing with air at the time of cold. Therefore, in the exhaust gas recirculation system S of Embodiment 1, a gas-liquid separation device 16 is provided at a position upstream of the low-pressure EGR valve 14 and a position upstream of the compressor 5a of the turbocharger 5 (a position enclosed by the dotted line X in FIG. 1), and condensed water is trapped by the gas-liquid separation device 16 and discharged. Figure 1

[0035] [Detailed structure of gas-liquid separation device]

[0036] Figure 2 is a cross-sectional view showing the gas-liquid separation device 16 of Embodiment 1. The gas-liquid separation device 16 of Embodiment 1 is provided with a pipe member 21, a swirl flow generation member 22, a water reservoir 23, and a bypass pipe 24.

[0037] One end of the pipe member 21 communicates with the intake port 2a and the low-pressure EGR valve 14, and the other end communicates with the compressor 5a of the turbocharger 5, and exhaust gas in which gas and liquid in the form of fine particles (condensed water) are mixed (hereinafter referred to as "gas-liquid two-phase fluid") flows. Also, the pipe member 21 is disposed so that the center axis O1 is in the horizontal direction when mounted on a vehicle, and is formed by linking three pipe-shaped bodies, a first pipe 25, a second pipe 26, and a third pipe 27. The first pipe 25, the second pipe 26, and the third pipe 27 are sequentially linked from the upstream side (the right side in FIG. 1, hereinafter referred to as "fluid inflow side") of the flow direction of the gas-liquid two-phase fluid toward the downstream side (the left side in FIG. 1, hereinafter referred to as "fluid outflow side"). Figure 2 Figure 2 The first pipe 25 is provided with a first swirl flow generation member 22a, and the second pipe 26 is provided with a second swirl flow generation member 22b. The third pipe 27 is provided with a water reservoir 23. The first pipe 25, the second pipe 26, and the third pipe 27 are linked by the bypass pipe 24.​​

[0038] Further, in the following description, the axial direction of the pipe member 21 (the direction along the center axis Ol) is referred to as "pipe axial direction", and the diametrical direction of the pipe member 21 (the direction orthogonal to the center axis Ol) is referred to as "pipe diametrical direction". Further, the circumferential direction of the pipe member 21 (the circumferential direction centered on the center axis Ol) is referred to as "pipe circumferential direction".

[0039] The first pipe 25 is a straight pipe member in which the swirl flow generating member 22 is arranged inside. The swirl region 22a in which the swirl flow generating member 22 is arranged, the tapered region 25b in which the inner diameter dimension of the first pipe 25 is gradually enlarged toward the fluid outflow side, and the stepped portion 25c which abuts against the second pipe 26 are formed inside the first pipe 25. Here, the tapered region 25b is formed further toward the fluid outflow side than the swirl region 22a. In addition, the stepped portion 25c is formed further toward the fluid outflow side than the tapered region 25b. The inner diameter dimension of the first pipe 25 is gradually increased in the order of the swirl region 22a, the tapered region 25b, and the stepped portion 25c.

[0040] The second pipe 26 is a T-shaped pipe member having a horizontal portion 26a which is connected to the first pipe 25, and a vertical portion 26b which is connected to the horizontal portion 26a in an orthogonal state.

[0041] One end of the horizontal portion 26a can be inserted into the first pipe 25, and in the state of being inserted into the first pipe 25, the horizontal portion 26a is in contact with the inner peripheral surface 25a of the first pipe 25. In addition, one end of the horizontal portion 26a abuts against the stepped portion 25c. The axial direction of the horizontal portion 26a coincides with the center axis Ol of the pipe member 21, and extends in the horizontal direction.

[0042] A drain opening 26c is formed at the connection portion of the horizontal portion 26a and the vertical portion 26b, and the horizontal portion 26a and the vertical portion 26b communicate with each other. The drain opening 26c is open to the gravitational direction (the lower side of the vertical direction of the center axis Ol), and the vertical portion 26b extends from the horizontal portion 26a in the gravitational direction. Thus, the liquid separated from the gas-liquid two-phase fluid flows down in the vertical portion 26b through the drain opening 26c by the weight.

[0043] Further, the vertical portion 26b is connected to a shape-reducing portion 26d in which the intermediate portion narrows toward the lower side and the flow passage area of the liquid gradually narrows. Thus, the opening area of a front end opening 26e formed at the front end (lower end) of the shape-reducing portion 26d is smaller than the opening area of the drain opening 26c. The vertical portion 26b, the drain opening 26c, the shape-reducing portion 26d, and the front end opening 26e correspond to a drain pipe.

[0044] The third pipe 27 is a straight pipe member having an outer diameter dimension such that a gap α is formed between the inner peripheral surface of the horizontal portion 26a and the third pipe 27 when the third pipe 27 is inserted into the horizontal portion 26a of the second pipe 26. The gap α is fitted with a spacer 28. The spacer 28 has a cylindrical shape that surrounds the entire periphery of the third pipe 27 and is in contact with the horizontal portion 26a of the second pipe 26 and the third pipe 27, respectively. That is, the other end of the horizontal portion 26a is closed by the spacer 28. In addition, the third pipe 27 is inserted into the second pipe 26 until an end portion 27a of the third pipe 27 is positioned above the drain opening 26c. Further, an air vent 27b is formed in the third pipe 27 at a position protruding from the second pipe 26. The second end portion 24b of the bypass pipe 24 is connected to the air vent 27b.

[0045] The water reservoir 23 has a tank main body 23a provided below the vertical portion 26b of the second pipe 26. A first opening 23b is formed in the upper surface of the tank main body 23a, a second opening 23c is formed in the side surface, and a drain opening, not shown, is formed in the bottom surface.

[0046] The first opening 23b is connected to the front end opening 26e of the vertical portion 26b via a communication pipe 23d. The first end portion 24a of the bypass pipe 24 is connected to the second opening 23c. The drain opening is appropriately opened and closed and is opened when the amount of liquid stored in the tank main body 23a reaches a certain amount, and the stored liquid can be discharged to the outside of the tank.

[0047] The bypass pipe 24 is a tubular body having both ends open, and the first end portion 24a is connected to the second opening 23c formed in the tank main body 23a, and the second end portion 24b is connected to the air vent 27b formed in the third pipe 27. Thus, the internal space of the tank main body 23a is in communication with the inside of the third pipe 27 via the bypass pipe 24.

[0048] [Detailed structure of the cyclone flow generating member]

[0049] The cyclone flow generating member 22 of Embodiment 1 is arranged in the cyclone region 22a of the first pipe 25, and defines the flow direction of the gas-liquid two-phase fluid flowing in the pipe member 21 so that the gas-liquid two-phase fluid becomes a cyclone flow. As shown in FIG. 2, the cyclone flow generating member 22 has a wing support portion 31 and a plurality of (four in this case) wing portions 32 provided to the outer peripheral surface 31a of the wing support portion 31. Figure 3A

[0050] Figure 3A ​​As shown, the wing support portion 31 has a conical shape in which the front end portion 31b is formed in an R face (fillet face). The swirl flow generating member 22 is disposed in the swirl region 22a in a direction in which the front end portion 31b is directed toward the fluid inflow side and the outer diameter dimension of the wing support portion 31 gradually increases toward the fluid outflow side. In addition, when the swirl flow generating member 22 is disposed in the swirl region 22a, the axial direction O2 of the wing support portion 31 coincides with the central axis OI of the pipe member 21. The maximum outer diameter dimension Rl (see Figure 3B ) of the wing support portion 31 is set to be smaller than the inner diameter dimension Dl (see Figure 2 ) of the swirl region 22a.

[0051] The plurality of (four) wing portions 32 protrude radially from the outer peripheral surface 31a of the wing support portion 31 and are disposed at equal angular intervals around the axial direction O2 of the wing support portion 31 with the axial direction O2 of the wing support portion 31 as a center, and spirally wrap around. Here, when the swirl flow generating member 22 is disposed in the swirl region 22a, the axial direction O2 of the wing support portion 31 coincides with the central axis OI of the pipe member 21. Therefore, each wing portion 32 extends while spirally bending with the central axis OI of the pipe member 21 as a center in a state in which the swirl flow generating member 22 is disposed in the swirl region 22a.

[0052] In addition, in Embodiment 1, the swirl flow generating member 22 is disposed in the swirl region 22a in a manner in which the end portions 32b of the fluid inflow side of each wing portion 32 extend alternately in the horizontal direction or the vertical direction when viewed from the pipe axial direction (see Figure 4 ).

[0053] Further, when the swirl flow generating member 22 is disposed in the swirl region 22a, the front end 32a in the pipe radial direction of the wing portion 32 of the plurality of wing portions 32 in which the notch portion 34a is not formed is in contact with the inner peripheral surface 25a (inner peripheral surface of the pipe member 21) of the first pipe 25 over the entire length of the axial direction O2 of the wing support portion 31. In addition, the portion of the wing portion 32 of the plurality of wing portions 32 in which the notch portion 34a is formed is in contact with the inner peripheral surface 25a (inner peripheral surface of the pipe member 21) of the first pipe 25 except for the notch portion 34a of the front end 32a in the pipe radial direction. That is, the maximum outer diameter dimension R2 (see Figure 3C ) of the swirl flow generating member 22 is set to be equal to the inner diameter dimension Dl of the swirl region 22a. On the other hand, the wrapping angle Θl of each wing portion 32 with respect to the wing support portion 31 is set to be approximately 90°. As Figure 3CAs shown, the "wrap-around angle θ1" refers to an angle formed by a protruding direction L1 of the end portion 32b of the wing portion 32 on the fluid inflow side and a protruding direction L2 of the end portion 32c of the wing portion 32 on the fluid outflow side when the swirl flow generating member 22 is viewed from the pipe axial direction. Since the wrap-around angle θ1 is approximately 90°, the end portion 32c of the wing portion 32 on the fluid outflow side overlaps the end portion 32b of the adjacent wing portion 32 on the fluid inflow side in the pipe axial direction when the swirl flow generating member 22 is viewed from the pipe axial direction. Further, due to the R shape (fillet shape) at the end portions 32b, 32c and the draft of the mold, the end portion 32b on the fluid inflow side and the end portion 32c on the fluid outflow side of the adjacent wing portion 32 sometimes do not overlap in the pipe axial direction.

[0054] Further, the swirl flow generating member 22 has the wrap-around angle θ1 of the plurality of (four) wing portions 32 set to approximately 90°, and thus, as shown, the leading end 32a of the wing portion 32 is continuous over the entire circumference of the pipe member 21 when viewed from the pipe axial direction. That is, when the swirl flow generating member 22 is viewed from the pipe axial direction, the central axis O1 of the pipe member 21 can be surrounded by a locus of the leading end 32a along the pipe radial direction of the wing portion 32. Thus, no gap extending in the pipe axial direction is generated between the side surfaces 32x of the adjacent wing portions 32 facing each other. Further, in the embodiment 1, as described below, although the notch portion 34a is formed at the leading end 32a of the wing portion 32, the notch portion 34a is also a part of the leading end 32a. Figure 4

[0055] Further, the gas-liquid separation device 16 of the embodiment 1 is provided with a communication portion 34 between the inner circumferential surface 25a of the pipe member 21, i.e., the first pipe 25, and the leading end 32a of the wing portion 32 of the swirl flow generating member 22. The communication portion 34 is a space extending in the pipe axial direction between the pipe member 21 and the swirl flow generating member 22 and communicating the first space X (see FIG. 2) upstream (on the fluid inflow side) of the swirl region 22a where the swirl flow generating member 22 is disposed with the second space Y (see FIG. 2) downstream (on the fluid outflow side) of the swirl region 22a where the swirl flow generating member 22 is disposed. Here, the communication portion 34 is provided by forming the notch portion 34a at the wing portion 32 of the swirl flow generating member 22. Further, the notch portion 34a is a portion in which a part of the leading end 32a of the wing portion 32 in the pipe radial direction is cut off. Figure 2 Figure 2

[0056] Further, the communication portion 34 has a predetermined width in the pipe circumferential direction. The swirl flow generating member 22 is disposed so as to adjust the orientation of the pipe circumferential direction when disposed in the swirl region 22a, and the central position 34b of the pipe circumferential direction of the communication portion 34 is located at a position lower than the central axis O1 of the pipe member 21 when viewed from the pipe axial direction. Further, the central position 34b of the communication portion 34 of the embodiment 1 is located below the central axis O1 in the vertical direction.​​​

[0057] Furthermore, the height H of the connecting portion 34 (the distance from the inner circumferential surface of the pipe member 21 to the radial direction of the wing 32) is set to approximately 5% of the radius of the pipe member 21. The height H of the connecting portion 34 is set to a certain height in any direction, both circumferentially and axially. In addition, the circumferential width W of the connecting portion 34 is set to approximately 25% of the circumference of the inner circumferential surface of the pipe member 21 (the inner circumferential surface 25a of the first pipe 25) in the spiral region 22a.

[0058] Next, the function of the gas-liquid separation device 16 in Example 1 will be explained in two parts: "liquid trapping function at high flow rates" and "liquid trapping function at low flow rates".

[0059] [Liquid trapping effect at high flow rates]

[0060] exist Figure 1 In the exhaust gas recirculation system S shown, external gas drawn in from the intake port 2a and exhaust gas drawn in from the exhaust port 3 via the low-pressure EGR passage 11 flow into the compressor 5a of the turbocharger 5 at a speed of 5 m / s to 110 m / s. The external gas and exhaust gas contain moisture. When the gas flowing into the compressor 5a is cooled by the EGR cooler 13, condensate is generated if the cooling water temperature is too low or the external gas temperature is low. This condensate mixes with the gas to form a gas-liquid two-phase fluid.

[0061] When the flow rate of the gas-liquid two-phase fluid is relatively high (e.g., 20 m / s to 110 m / s), the condensate becomes fine particles and flows mixed with the gas.

[0062] like Figure 2 As shown, in the gas-liquid separation device 16 of Embodiment 1, a swirling flow generating member 22 is disposed inside the first tube 25 of the tube member 21. The swirling flow generating member 22 has a plurality of wing portions 32 that protrude radially from the outer peripheral surface 31a of the wing support portion 31 and extend spirally around the central axis O1 of the tube member 21.

[0063] Therefore, as Figure 5As shown, the gas-liquid two-phase fluid flowing into the pipe member 21 flows along the wing portion 32 when passing through the swirling region 22a provided with the swirling flow generating member 22, whereby the flow direction is defined, becoming swirling flow flowing while swirling. Further, the liquid of large mass is guided toward the inner peripheral surface 25a of the first pipe 25 by the centrifugal force generated by the swirling of the gas-liquid two-phase fluid. The liquid guided toward the inner peripheral surface 25a of the first pipe 25 adheres to the inner peripheral surface 25a of the first pipe 25, coagulates to become water droplets, and is separated from the gas. On the other hand, the air from which the liquid has been separated flows linearly along the pipe axis while swirling, flows from the first pipe 25 to the second pipe 26, and flows into the third pipe 27.

[0064] On the other hand, as shown in FIG. 6, the gas-liquid two-phase fluid flowing into the pipe member 21 flows along the wing portion 32 when passing through the swirling region 22a provided with the swirling flow generating member 22, whereby the flow direction is defined, becoming swirling flow flowing while swirling. Further, the liquid of large mass is guided toward the inner peripheral surface 25a of the first pipe 25 by the centrifugal force generated by the swirling of the gas-liquid two-phase fluid. The liquid guided toward the inner peripheral surface 25a of the first pipe 25 adheres to the inner peripheral surface 25a of the first pipe 25, coagulates to become water droplets, and is separated from the gas. On the other hand, the air from which the liquid has been separated flows linearly along the pipe axis while swirling, flows from the first pipe 25 to the second pipe 26, and flows into the third pipe 27. Figure 5

[0065] Thus, the gas-liquid separation device 16 of Embodiment 1 is able to swirl the gas-liquid two-phase fluid by the swirling flow generating member 22 when the gas-liquid two-phase fluid flows at a high flow rate, and separate the gas and the liquid by the centrifugal force. In addition, the gas-liquid separation device 16 of Embodiment 1 is able to capture the water storage tank 23 while suppressing the re-dispersion of the liquid by guiding the liquid toward the inner peripheral surface 25a of the first pipe 25 and causing it to adhere to the inner peripheral surface 25a.

[0066] [Effect of liquid capture at low flow rate]

[0067] In the exhaust gas recirculation system S of Embodiment 1, when the flow rate of the gas-liquid two-phase fluid is relatively slow (at a low flow rate, for example, 5 m / s to 20 m / s), the condensed water is difficult to become fine particles. In this case, as shown in FIG. 7, the gas and the liquid naturally separate before the gas-liquid two-phase fluid flows into the swirling region 22a provided with the swirling flow generating member 22, that is, before swirling, the liquid that has become water droplets adheres to the inner peripheral surface 25a of the first pipe 25. In addition, the gas flows along the wing portion 32 when passing through the swirling region 22a, becomes swirling flow, flows linearly along the pipe axis while swirling, flows from the first pipe 25 to the second pipe 26, and flows into the third pipe 27. Figure 6

[0068] On the other hand, the liquid adhering to the inner peripheral surface 25a of the first pipe 25 is unable to flow in a mixed phase with the gas, and flows toward the swirling region 22a in a state of adhering to the inner peripheral surface 25a of the first pipe 25 by the flow of the gas. ​​

[0069] In this embodiment 1, the swirl flow generating member 22 has the wing portion 32 surrounding the wing support portion 31. Also, the front end 32a of the wing portion 32 in the tube radial direction is in contact with the inner peripheral surface 25a of the first tube 25, and the surrounding angle θ1 with respect to the wing support portion 31 is set to about 90°, and the front end 32a is continuous on the entire circumference of the tube member 21 when viewed from the tube axial direction. Further, a communication portion 34 is provided between the inner peripheral surface 25a of the first tube 25 and the wing portion 32 of the swirl flow generating member 22. The communication portion 34 extends along the tube axial direction between the first tube 25 and the swirl flow generating member 22, and communicates the first space X more upstream than the swirl region 22a and the second space Y more downstream than the swirl region 22a.

[0070] Therefore, the liquid (water droplets) separated from the gas before flowing into the swirl region 22a flows in the communication portion 34, and thus can flow horizontally with respect to the central axis Ol inside the tube member 21, and can flow from the first space X into the second space Y. That is, the liquid adhering to the inner peripheral surface 25a of the first tube 25 is not hindered from flowing by the swirl flow generating member 22, and can smoothly pass through the swirl region 22a.

[0071] Then, the liquid that has passed through the swirl region 22a flows toward the second tube 26 while adhering to the inner peripheral surface 25a of the first tube 25, passes through the tapered region 25b, and flows into the second tube 26. The liquid flowing into the second tube 26 flows while adhering to the inner peripheral surface 26f of the second tube 26, flows into the drain opening 26c, and flows down in the vertical portion 26b. Thereafter, the liquid is discharged through the front end opening 26e and stored in the can body 23a.

[0072] Thus, in the gas-liquid separation device 16 of embodiment 1, even in a case where the gas and the liquid are naturally separated before flowing into the swirl region 22a, even if the flow rate of the gas-liquid two-phase fluid is slow, the liquid can flow through the communication portion 34 provided between the inner peripheral surface 25a of the first tube 25 and the wing portion 32. Therefore, even if the front end 32a of the wing portion 32 is continuous on the entire circumference of the tube member 21 when viewed from the tube axial direction, the flow of the liquid is not hindered by the wing portion 32, and the liquid can be trapped on the fluid outflow side of the swirl flow generating member 22. As a result, the liquid can be trapped at a position more downstream than the swirl flow generating member 22, regardless of the flow rate of the gas-liquid two-phase fluid.

[0073] Further, the communication portion 34 is a space formed on a part of the tube circumferential direction between the inner peripheral surface 25a of the first tube 25 and the wing portion 32. Therefore, the front end 32a of the wing portion 32 is in contact with the inner peripheral surface 25a of the first tube 25 except for a portion opposite the communication portion 34. Therefore, the swirl flow generating member 22 can be supported by the tube member 21, and the strength of the swirl flow generating member 22 against vibration can be ensured.

[0074] Further, in the gas-liquid separation device 16 of Embodiment 1, the communication portion 34 is formed by the notch portion 34a formed in the wing portion 32. Therefore, it is not necessary to form a concave-convex on the inner peripheral surface 25a of the first pipe 25, and the first pipe 25 can be easily formed.

[0075] Further, the position of the communication portion 34 in the pipe circumferential direction can be defined by the direction of the pipe circumferential direction when the cyclone flow generating member 22 is disposed in the cyclone region 22a. Therefore, the position of the communication portion 34 in the pipe circumferential direction can be easily finely adjusted.

[0076] Further, in the gas-liquid separation device 16 of Embodiment 1, the central position 34b of the communication portion 34 in the pipe circumferential direction is located at a position lower than the center axis Oi of the pipe member 21 in the direction of gravity when viewed from the pipe axis. Thus, liquid that has flowed down to the lower portion of the pipe member 21 (the first pipe 25) by the self-weight can flow into the communication portion 34, and therefore the collection of the liquid can be smoothly performed.

[0077] In particular, in Embodiment 1, the central position 34b of the communication portion 34 in the pipe circumferential direction is located below the vertical direction of the center axis Oi of the pipe member 21. Therefore, liquid that has flowed down to the lower portion of the pipe member 21 by the gravity can reliably flow into the communication portion 34.

[0078] Further, in the gas-liquid separation device 16 of Embodiment 1, a gap a is generated between the second pipe 26 and the third pipe 27. Therefore, liquid adhered to the inner peripheral surface 26f of the second pipe 26 enters the gap a, and the liquid can be prevented from flowing into the third pipe 27. Further, because the third pipe 27 of the fluid outflow side is inserted into the second pipe 26, the increase in the outer diameter dimension of the pipe member 21 can be suppressed, and thus the space required for the installation of the gas-liquid separation device 16 can be suppressed.

[0079] Further, in Embodiment 1, the partition member 28 that closes the gap a is fitted to the other end of the horizontal portion 26a of the second pipe 26. Therefore, the gas can be prevented from leaking out between the second pipe 26 and the third pipe 27, and the gas can be smoothly flowed into the third pipe 27.

[0080] Further, in Embodiment 1, the third pipe 27 and the water reservoir 23 are communicated via the bypass pipe 24. Therefore, the inside of the water reservoir 23 can be made to be under a negative pressure by the gas flow in the third pipe 27, and thus the flow of liquid that has flowed down in the vertical portion 26b can be made to be smooth. Further, in Embodiment 1, Figure 2 In Embodiment 1, the bypass pipe 24 is connected to the second opening 23c formed in the side surface of the tank main body 23a, but is not limited thereto, and for example, the bypass pipe 24 can be connected to an opening formed in the upper surface of the tank main body 23a.

[0081] The gas-liquid separation device of the present application has been described above based on Embodiment 1, but the specific structure is not limited to this embodiment 1, and design changes or additions, etc. are allowed as long as the gist of the invention of each claim of the claims is not deviated from.

[0082] In the gas-liquid separation device 16 of Embodiment 1, the pipe circumferential central position 34b of the communication portion 34 is located vertically downward from the center axis O1 of the pipe member 21. However, the position of the communication portion 34 is not limited to this. For example, as shown in Figure 7 , the pipe circumferential central position 34b of the communication portion 34 can also be set at a position that is offset by a predetermined angle from the vertically downward position with respect to the center axis O1 in the swirling direction of the gas-liquid two-phase fluid generated by the swirling flow generating member 22 (clockwise direction in Figure 7 ).

[0083] Thus, even if a part of the liquid adhering to the inner circumferential surface 25a of the first pipe 25 flows in the pipe circumferential direction due to the swirling flow, the liquid can flow into the communication portion 34. Therefore, in the gas-liquid separation device 16 of Embodiment 1, the flow of the liquid is not hindered by the swirling flow generating member 22, and the liquid can be properly trapped downstream of the swirling flow generating member 22.

[0084] Further, the swirling direction of the swirling flow generating member 22 is not limited to the clockwise direction as shown in Figure 7 , but can also swirl in the opposite direction. Further, the angle by which the pipe circumferential central position 34b of the communication portion 34 is offset with respect to the vertical direction, i.e., the angle θ2 formed by the vertical direction line L3 passing through the center axis O1 and the straight line L4 passing through the center axis O1 and the pipe circumferential central position 34b of the communication portion 34, can be arbitrarily set within a range of about 90° or less.

[0085] In addition, the position of the communication portion 34 and the protruding direction L1 of the end portion 32b of each wing portion 32 on the fluid inflow side when viewed from the pipe axis direction can be arbitrarily set. That is, as shown in Figure 7 , when the pipe circumferential central position 34b of the communication portion 34 is set at a position that is offset by a predetermined angle from the vertically downward position with respect to the center axis O1, the end portion 32b on the fluid inflow side of one wing portion 32 can also be set to extend along the straight line L4 passing through the center axis O1 and the pipe circumferential central position 34b of the communication portion 34 when viewed from the pipe axis direction. In addition, as shown in Figure 8As shown, the central position 34b of the tube circumferential direction of the communication portion 34 is set to a position that is offset by a prescribed angle from the vertically lower position of the central axis O1, and on the other hand, the end portions 32b of the fluid inflow side of the plurality of wing portions 32 can also be set to extend alternately in the horizontal direction or the vertical direction as viewed from the tube axis direction. Further, although not shown, the central position 34b of the tube circumferential direction of the communication portion 34 can be set to the vertically lower position of the central axis O1, and on the other hand, the end portions 32b of the fluid inflow side of the plurality of wing portions 32 can also be set to extend in directions that are offset from the horizontal direction and the vertical direction, respectively.

[0086] In addition, in the gas-liquid separation device 16 of Embodiment 1, an example is shown in which the height H of the communication portion 34 is set to a certain height in any direction of the tube axis direction and the tube circumferential direction. However, the height H of the communication portion 34 is not limited to this. For example, as shown in Figure 9 , it is also possible to set the height H of a portion of the tube circumferential direction of the communication portion 34 (in the example shown in Figure 9 , the central position 34b of the tube circumferential direction of the communication portion 34) to be relatively higher than other portions (in the example shown in Figure 9 , the two end portions of the tube circumferential direction). Thereby, the gas-liquid separation device 16 can cause the liquid that has gathered at the central position 34b of the tube circumferential direction of the communication portion 34 to flow quickly. Furthermore, the height H of the communication portion 34 can gradually change along the tube circumferential direction, but is not limited to this, and can also change in steps along the tube circumferential direction. Figure 9

[0087] In addition, in the gas-liquid separation device 16 of Embodiment 1, an example is shown in which the swirl flow generation member 22 has a wing support portion 31 that is conical in shape and a plurality of wing portions 32 that protrude from the outer peripheral surface 31a of the wing support portion 31. However, the shape of the swirl flow generation member 22 is not limited to this, and for example, the swirl flow generation member can also be formed by a plate member that is twisted in a spiral shape. That is, as long as it is a gas-liquid separation device that has a swirl flow generation member that has wing portions that extend in a spiral shape with the central axis O1 of the tube member 21 as the center, and the leading ends of the tube radial direction as viewed from the tube axis direction are continuous over the entire circumference of the tube member 21, the present application can be applied.

[0088] In addition, in Embodiment 1, an example is shown in which the four wing portions 32 of the swirl flow generation member 22 are set to be approximately 90° in the wraparound angle θ1. However, as long as the leading end 32a of the wing portion 32 of the swirl flow generation member 22 is continuous over the entire circumference of the tube member 21 as viewed from the tube axis direction, the number of wing portions 32 or the angle of the wraparound angle θ1 can be set arbitrarily.

[0089] ​Furthermore, in Embodiment 1, the connecting portion 34 is provided by forming a notch 34a in the wing 32. However, the structure of the connecting portion 34 is not limited to this. For example, the connecting portion 34 may also be formed by the notch 34a formed at the front end 32a of the wing 32 facing a groove extending axially in the inner peripheral surface 25a of the first pipe 25 of the pipe member 21. That is, the connecting portion 34 may be formed only in the swirling flow generating member 22, or it may be formed in both the pipe member 21 and the swirling flow generating member 22.

[0090] Additionally, in Embodiment 1, an example is shown where the water storage tank 23 is connected to the front opening 26e of the vertical section 26b, but the vertical section 26b or the water storage tank 23 may not necessarily be provided. Liquid discharged from the drain opening 26c can be discharged directly to the outside of the pipe member 21 without storage. Furthermore, a bypass pipe 24 is not necessarily required.

[0091] Additionally, in Example 1, it is shown that in the exhaust recirculation system S, at the downstream position of the low-pressure EGR valve 14 and the upstream position of the compressor 5a of the turbocharger 5 (in... Figure 1 The example shown is a gas-liquid separator 16 located at the position enclosed by the dashed line X, but it is not limited to this. Since the gas-liquid separator 16 is located at the point where condensate is generated in the exhaust recirculation system S, it can also be located downstream of the intercooler 6 and upstream of the cylinder intake port of the internal combustion engine 1 (in...). Figure 1 (The position enclosed by the dotted-dash line Y).

[0092] Furthermore, in Embodiment 1, an example is shown where the internal combustion engine 1 is a diesel engine mounted in a vehicle, but it is not limited thereto; it can also be applied even if the internal combustion engine 1 is a gasoline engine.

[0093] Furthermore, in Embodiment 1, an example is shown of the gas-liquid separator 16 being applied to the exhaust gas recirculation system S of an internal combustion engine 1. However, the application of the gas-liquid separator 16 is not limited to this; for example, the gas-liquid separator 16 can also be applied to a refrigeration cycle device to separate the gaseous refrigerant from the liquid refrigerant. That is, the gas-liquid separator of the present invention can be applied to a device for separating gas and liquid from a gas-liquid two-phase fluid.

[0094] Furthermore, the shape of the pipe component 21, the connecting parts such as the first pipe 25, the diameter, the materials used, etc., are not limited to those shown in Embodiment 1, and can be set arbitrarily.

[0095] Cross-reference of related applications

[0096] This application claims priority based on Japanese Patent Application No. 2020-219258 filed with the Japanese Patent Office on December 28, 2020, the entire disclosure of which is incorporated herein by reference.

Claims

1. A gas-liquid separation device provided with a pipe member through which a gas-liquid two-phase fluid flow in which a gas and a liquid are mixed flows, and a swirl flow generating member arranged inside a first pipe of the pipe member, the gas-liquid two-phase fluid being separated by the gas and the liquid by the swirl flow generating member causing the gas-liquid two-phase fluid to swirl, characterized in that the swirl flow generating member has a wing support portion and a plurality of wing portions provided to an outer circumferential surface of the wing support portion, the wing portions extending in a spiral shape around a central axis of the pipe member, a communication portion is provided between the pipe member and the swirl flow generating member, the communication portion communicating a first space upstream of the swirl flow generating member and a second space downstream of the swirl flow generating member, the communication portion being provided by forming a notch portion in the wing portions, the notch portion being a portion in which a part of a front end in a pipe radial direction of the wing portions is cut off, when the swirl flow generating member is arranged in a swirling region, the front end in the pipe radial direction of the wing portions of the plurality of wing portions in which the notch portion is not formed is in contact with an inner circumferential surface of the first pipe over the entire length in an axial direction of the wing support portion, and a portion of the wing portions of the plurality of wing portions in which the notch portion is formed at the front end is in contact with the inner circumferential surface of the first pipe except for the notch portion of the front end in the pipe radial direction.

2. The gas-liquid separation device according to claim 1, characterized in that a central position of the communication portion in a pipe circumferential direction is located at a position lower than the central axis in a gravitational direction.

3. The gas-liquid separation device according to claim 2, characterized in that the central position of the communication portion in the pipe circumferential direction is offset more to a swirling direction of the gas-liquid two-phase fluid generated by the swirl flow generating member than a plumb lower position of the central axis. ​ ​ ​ ​ ​

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