Supercharger gas casing and supercharger

Abstract

A supercharger gas casing is provided with a scroll portion that forms a plurality of scroll flow paths at the same position in the axial direction of a turbine, the plurality of scroll flow paths including a first scroll flow path configured such that, in a cross section of the turbine orthogonal to the axial direction, an extension line of a line segment connecting a position farthest from a rotational axis of the turbine at an inlet of exhaust gas of the first scroll flow path and a position of a front end of a tongue portion formed on an inner peripheral side of the first scroll flow path does not intersect with a moving blade of the turbine.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a supercharger gas casing and a supercharger.

[0002] This application claims priority from Japanese Patent Application No. 2021-066025 filed on April 8, 2021, and the content thereof is hereby incorporated by reference. BACKGROUND

[0003] In a supercharger, erosion occurs due to the collision of engine combustion residues with a turbine.

[0004] In Patent Literature 1, it is described that, in order to suppress erosion of a scroll flow path of a turbine in a supercharger, a protruding portion protruding toward the radial inner side is provided to a flow path wall surface of the scroll flow path, so as to disperse combustion residues colliding with the flow path wall surface.

[0005] PRIOR ART DOCUMENTS

[0006] PATENT LITERATURE

[0007] Patent Literature 1: Japanese Patent Application Publication No. H11-303642 SUMMARY

[0008] PROBLEMS TO BE SOLVED BY THE INVENTION

[0009] However, in a turbine of a double-scroll structure having a plurality of scroll flow paths at the same position in the axial direction of the turbine, combustion residues of the engine flowing into the scroll flow paths are likely to collide with the turbine vanes, and thus erosion of the turbine vanes is likely to occur. In this regard, no insight for suppressing erosion of the turbine vanes in a turbine of a double-scroll structure is disclosed in Patent Literature 1.

[0010] In view of the above, an object of at least one aspect of the present disclosure is to provide a supercharger gas casing capable of suppressing erosion of turbine vanes in a turbine of a double-scroll structure, and a supercharger provided with the supercharger gas casing.

[0011] SOLUTION TO THE PROBLEM

[0012] To achieve the above object, a supercharger gas casing of at least one aspect of the present disclosure is a supercharger gas casing of a turbine of a supercharger, in which

[0013] The supercharger gas casing has a scroll portion that forms a plurality of scroll flow paths at the same position in the axial direction of the turbine,

[0014] The plurality of scroll flow paths includes a first scroll flow path,

[0015] The first scroll flow path is configured such that, in a cross section of the turbine orthogonal to an axial direction, an extension line of a line segment connecting a position, at which the exhaust gas of the first scroll flow path enters, farthest from a rotation axis of the turbine and a position of a tip of a tongue portion formed on an inner peripheral side of the first scroll flow path does not cross a blade of the turbine.

[0016] To achieve the above object, a supercharger according to at least one aspect of the present disclosure includes:

[0017] The supercharger gas casing described above;

[0018] A turbine wheel; and

[0019] A compressor impeller linked to the turbine wheel via a rotation shaft.

[0020] Effects of Invention

[0021] According to at least one aspect of the present disclosure, a supercharger gas casing capable of suppressing erosion of a blade in a turbine of a double-scroll structure and a supercharger including the same are provided. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a view schematically showing a supercharger 2 of an embodiment.

[0023] Figure 2 is a view schematically showing Figure 1 a cross section orthogonal to an axial direction in the turbine 6 shown.

[0024] Figure 3 is a view showing trajectories of fine particles (CFD results) in the scroll flow path 024 and the scroll flow path 26, respectively.

[0025] Figure 4 is a view showing trajectories of coarse particles (CFD results) in the scroll flow path 024 and the scroll flow path 26, respectively.

[0026] Figure 5 is a view showing trajectories of coarse particles in the scroll flow path 24 and the scroll flow path 26, respectively.

[0027] Figure 6 is a view schematically showing Figure 2 a cross section of an example of a structure of the turbine 6 shown.

[0028] Figure 7 is a view for explaining Figure 6 effects of the protrusion portions 40, 42 shown.

[0029] Figure 8 is a view for explaining Figure 2Cross-sectional views of several examples of the structure of turbine 6 are shown.

[0030] Figure 9A It is shown Figure 8 Schematic diagrams of an example of section A1-A1 and section A2-A2.

[0031] Figure 9B It is shown Figure 8 Schematic diagrams of another example of section B1-B1 and another example of section B2-B2.

[0032] Figure 9C It is shown Figure 8 Schematic diagrams of an example of section C1-C1 and section C2-C2.

[0033] Figure 10A It is shown Figure 8 Schematic diagrams of another example of section A1-A1 and another example of section A2-A2.

[0034] Figure 10B It is shown Figure 8 Schematic diagrams of another example of section B1-B1 and another example of section B2-B2.

[0035] Figure 10C It is shown Figure 8 Schematic diagrams of another example of section C1-C1 and another example of section C2-C2. Detailed Implementation

[0036] Hereinafter, several embodiments of the present disclosure will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the constituent components described as embodiments or shown in the drawings are not intended to limit the scope of the invention, but are merely illustrative examples.

[0037] For example, expressions such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric" or "coaxial" indicate relative or absolute configurations, not only in a strict sense, but also in a state of relative displacement by angle or distance with tolerance or to the extent that the same function can be obtained.

[0038] For example, expressions such as "same," "equal," and "homogeneous" that indicate the state of equality of things not only indicate a state of strict equality, but also indicate a state of difference in the degree to which the same function can be obtained due to the existence of tolerances.

[0039] For example, the descriptions of shapes such as quadrilaterals and cylindrical shapes not only refer to quadrilaterals and cylindrical shapes in a strict geometric sense, but also to shapes that include concave and convex parts, chamfered parts, etc., within the range where the same effect can be obtained.

[0040] On the other hand, the expressions "have", "contain", "provide", "include", or "possess" one component are not exclusive expressions that exclude the presence of other components.

[0041] Figure 1 is a view schematically showing a turbocharger 2 of an embodiment. The turbocharger 2 can also be a turbocharger for a ship.

[0042] As shown in Figure 1 , the turbocharger 2 has a compressor 4 and a turbine 6 that are coupled to each other. A compressor impeller 8 of the compressor 4 and a turbine working wheel 10 of the turbine 6 are coupled via a rotation shaft 9 and configured to rotate integrally.

[0043] If the turbine working wheel 10 is driven by exhaust gas discharged from an engine not shown, the rotation of the turbine working wheel 10 is transmitted to the compressor impeller 8 via the rotation shaft 9 to rotate the compressor impeller 8, and air is compressed by the rotation of the compressor impeller 8. The compressed air ejected from the compressor 4 is supplied to the engine not shown.

[0044] Hereinafter, the axial direction of the turbine 6, i.e., the axial direction of the rotation shaft 9 is simply referred to as "axial direction", the circumferential direction of the turbine 6, i.e., the circumferential direction of the rotation shaft 9 is simply referred to as "circumferential direction", and the radial direction of the turbine 6, i.e., the radial direction of the rotation shaft 9 is simply referred to as "radial direction". In addition, the exhaust gas discharged from the engine not shown and supplied to the turbine 6 is simply referred to as "exhaust gas".

[0045] Figure 2 is a view schematically showing Figure 1 a cross section orthogonal to the axial direction in the turbine 6 shown in Figure 2 . As shown in

[0046] The turbine working wheel 10 includes a hub 16 and a plurality of blades 18 provided at intervals in the circumferential direction on an outer peripheral surface of the hub 16.

[0047] The plurality of nozzle vanes 12 are provided at intervals in the circumferential direction on the outer peripheral side of the turbine working wheel 10.

[0048] The gas casing 14 includes a working wheel housing portion 20 that houses the turbine working wheel 10, a nozzle passage portion 22 in which the plurality of nozzle vanes 12 are arranged, and a scroll portion 23 that forms a plurality of scroll flow paths 24, 26 at the same position in the axial direction. The plurality of scroll flow paths 24, 26 include a scroll flow path 24 and a scroll flow path 26. Thus, the turbine 6 is a turbine having a structure of two scroll flow paths 24, 26 at the same position in the axial direction, i.e., a double-scroll structure.

[0049] The working wheel housing 20 extends in a cylindrical shape along the axial direction and is configured to guide the exhaust gas passing through the turbine working wheel 10 to the exhaust gas outlet of the turbine 6.

[0050] The nozzle passage 22 forms an annular space between the vortex section 23 and the impeller housing 20. The nozzle passage 22 connects the vortex flow path 24 to the impeller housing 20 within a first circumferential range (180 degrees in the illustrated example), and connects the vortex flow path 26 to the impeller housing 20 within a second circumferential range (180 degrees in the illustrated example, excluding the first range). Exhaust gas passing through the vortex flow path 24 or vortex flow path 26 is guided towards the turbine impeller 10 by the plurality of nozzle blades 12 disposed in the nozzle passage 22.

[0051] The vortex flow paths 24 and 26 are arranged circumferentially at the same position in the axial direction. In the illustrated exemplary manner, the extension direction of the vortex flow path 24 at the inlet 24a (the opening on the inlet side of the vortex flow path 24) is at an angle of less than 180 degrees (approximately 90 degrees in the illustrated example) to the extension direction of the vortex flow path 26 at the inlet 26a (the opening on the inlet side of the vortex flow path 26).

[0052] like Figure 2 As shown, the vortex flow path 24 is curved in the following manner: In a cross-section orthogonal to the axial direction in the turbine 6, with P1 being the position furthest from the rotation axis O of the turbine 6 at the exhaust gas inlet 24a of the vortex flow path 24, Q1 being the position of the front end of the tongue 25 formed on the inner circumference side of the vortex flow path 24, and L1a being the extension line obtained by extending the line segment L1 connecting position P1 and position Q1 in a straight line, the extension line L1a does not intersect with the moving blade 18 of the turbine 6 when the turbocharger 2 is assembled. That is, the vortex flow path 24 is curved in such a way that the moving blade 18 of the turbine 6 cannot be seen from the inlet 24a when observing the interior of the vortex flow path 24 from the exhaust gas inlet 24a. It should be noted that the position Q1 of the front end of the tongue 25 corresponds to the position where the downstream end of the vortex flow path 26 connects to the vortex flow path 24.

[0053] In the illustrative manner shown in the figure, the vortex flow path 24 includes a straight flow path section 28 extending in a straight line and a vortex flow path section 30 extending in a vortex shape along the circumference. The vortex flow path section 30 is curved in such a way that when the interior of the vortex flow path 24 is viewed from the inlet 24a of the exhaust gas formed in the straight flow path section 28, the moving blade 18 of the turbine 6 is not visible from the inlet 24a.

[0054] Furthermore, the vortex flow path 24 is curved in such a way that the aforementioned extension line L1a does not intersect with the nozzle blade 12 in a cross section orthogonal to the axial direction in the turbine 6. That is, the vortex flow path 24 is curved in such a way that the nozzle blade 12 is not visible from the inlet 24a when the interior of the vortex flow path 24 is viewed from the exhaust gas inlet 24a.

[0055] like Figure 2 As shown, the vortex flow path 26 is curved in the following manner: In a cross-section orthogonal to the axial direction in the turbine 6, with P2 being the position furthest from the rotation axis O of the turbine 6 at the exhaust gas inlet 26a of the vortex flow path 26, Q2 being the position of the front end of the tongue 32 formed on the inner circumference side of the vortex flow path 26, and L2a being the extension of the line segment L2 connecting position P2 and position Q2, the extension line L2a does not intersect the moving blade 18 of the turbine 6 when the turbocharger 2 is assembled. That is, the vortex flow path 26 is curved in such a way that the moving blade 18 of the turbine 6 cannot be seen from the inlet 26a when observing the interior of the vortex flow path 26 from the exhaust gas inlet 26a. It should be noted that the position Q2 of the front end of the tongue 32 corresponds to the position where the downstream end of the vortex flow path 24 connects to the vortex flow path 26.

[0056] In the illustrated exemplary configuration, the vortex flow path 26 includes a straight flow path section 33 extending in a straight line and a vortex flow path section 34 extending in a circumferential vortex shape. The vortex flow path section 34 is curved such that when the interior of the vortex flow path 26 is viewed from the inlet 26a of the exhaust gas formed in the straight flow path section 33, the moving blades 18 of the turbine 6 are not visible from the inlet 26a. The vortex flow path section 34 extends along the outer peripheral side of the vortex flow path section 30 and connects to the nozzle passage section 22. The downstream end of the vortex flow path section 34 is connected to the inner peripheral end of the vortex flow path 24 via the inner peripheral side of the straight flow path section 28 of the vortex flow path 24, thereby forming the aforementioned tongue 25. The downstream end of the vortex flow path section 30 is connected to the inner peripheral end of the vortex flow path section 34 via the inner peripheral side of the vortex flow path section 34 of the vortex flow path 26, thereby forming the aforementioned tongue 32.

[0057] Furthermore, the vortex flow path 26 is curved in such a way that the aforementioned extension line L2a does not intersect with the nozzle blade 12 in a cross section orthogonal to the axial direction in the turbine 6. That is, the vortex flow path 26 is curved in such a way that the nozzle blade 12 is not visible from the inlet 26a when the interior of the vortex flow path 26 is viewed from the exhaust gas inlet 26a.

[0058] like Figure 2 As shown, in the cross-section orthogonal to the axial direction in the turbine 6, the inner wall surface 36 (flow path wall surface of the vortex flow path 24) of the vortex flow path 24 includes an outwardly facing portion 36o towards the radially outward side and an inwardly facing portion 36i towards the radially inward side. Figure 2In the cross-section shown, when P3 is defined as the position closest to the rotation axis O of the turbine 6 in the inlet 24a of the vortex flow path 24, the outwardly facing portion 36o is the part of the inner wall surface 36 of the vortex flow path 24 that connects position P3 and position Q1. The outwardly facing portion 36o corresponds to the wall surface located on the inner circumferential side of the inner wall surface 36 of the vortex flow path 24. Furthermore, in Figure 2 In the cross-section shown, the inward-facing portion 36i is the part of the inner wall surface 36 of the vortex flow path 24 that connects positions P1 and Q2 in the vortex flow path 24. The inward-facing portion 36i corresponds to the wall surface of the inner wall surface 36 of the vortex flow path 24 located on the outer periphery of the vortex flow path 24.

[0059] Here, the surface roughness Ra (arithmetic mean roughness of the inner face 36i) is greater than the surface roughness Ra (arithmetic mean roughness of the outer face 36o), for example, it can be 25 μm or more.

[0060] like Figure 2 As shown, in the cross-section orthogonal to the axial direction in the turbine 6, the inner wall surface 38 (flow path wall surface of the vortex flow path 26) of the vortex flow path 26 includes an outer surface 38o facing outward in the radial direction and an inner surface 38i facing inward in the radial direction. Figure 2 In the cross-section shown, when P4 is defined as the position in the inlet 26a of the vortex flow path 26 closest to the rotation axis O of the turbine 6, the outwardly facing portion 38o is the part of the inner wall surface 38 of the vortex flow path 26 that connects position P4 and position Q2. The outwardly facing portion 38o corresponds to the wall surface located on the inner circumferential side of the inner wall surface 38 of the vortex flow path 26. Furthermore, in Figure 2 In the cross-section shown, the inward-facing portion 38i is the part of the inner wall surface 38 of the vortex flow path 26 that connects position P2 and position Q1 in the vortex flow path 26. The inward-facing portion 38i corresponds to the wall surface of the inner wall surface 38 of the vortex flow path 26 located on the outer periphery of the vortex flow path 26.

[0061] Here, the surface roughness Ra (arithmetic mean roughness of the inner face 38i) is greater than the surface roughness Ra (arithmetic mean roughness of the outer face 38o), for example, it can be 25 μm or more.

[0062] Here, about Figure 3 The effect of the gas casing 14 shown is the same as... Figure 3 The structures shown are compared and explained.

[0063] Turbo 6 has Figure 3In the case of the vortex flow path 024 with the shape shown (the vortex flow path 024, in which the inlet 024a and the moving blade 18 are connected in a straight line by the aforementioned extension line L1a intersecting with the moving blade 18 of the turbine 6), the exhaust gas of the engine (not shown) contains fine particles smaller than a few μm in the combustion residue, such as... Figure 3 As shown, it follows the flow of exhaust gas, thus flowing into the pressure surface (ventral side) of the moving blade 18, passing between the moving blades 18. On the other hand, in Figure 4 In the structure shown, the large particles larger than 10μm in the combustion residue contained in the engine exhaust gas do not follow the flow of exhaust gas due to their high inertial force, but rather... Figure 2 As shown, it collides with the negative pressure surface (back side) of the moving blade 18 of the turbine impeller 10, thus causing erosion of the moving blade 18.

[0064] In contrast, according to Figure 5 The gas casing 14 shown has a vortex flow path 24 that bends in a manner that does not intersect the aforementioned extension line L1a with the moving blade 18 of the turbine 6, thus preventing coarse particles contained in the exhaust gas from being contained within it. Figure 5 As shown by arrow a1, the particles collide with the inner wall surface 36 of the vortex flow path 24 before colliding with the moving blade 18. Furthermore, according to the inventors' understanding, even if the coarse particles that collide with the inner wall surface 36 of the vortex flow path 24 flow downstream, their impact on the erosion of the moving blade 18 is limited. Therefore, it is possible to suppress the direct collision between coarse particles in the exhaust gas flowing into the vortex flow path 24 and the moving blade 18 of the turbine 6, thereby suppressing the erosion of the moving blade 18 of the turbine 6.

[0065] Furthermore, since the vortex flow path 24 bends in such a way that its extension line L1a does not intersect with the nozzle blade 12 of the turbine 6, the coarse particles contained in the exhaust gas, such as... Figure 2 As shown by arrow a1, the particles collide with the inner wall surface 36 of the vortex flow path 24 before passing between adjacent nozzle blades 12. Therefore, it is possible to suppress the guidance of coarse particles contained in the exhaust gas from the nozzle blades 12 to the moving blades 18 of the turbine 6, and to effectively suppress the erosion of the moving blades 18 of the turbine 6.

[0066] Furthermore, the surface roughness Ra of the inner face 36i is greater than that of the outer face 36o, so particles that collide with the inner face 36i are easily refined through friction with the inner face 36i as they flow downstream. Additionally, compared to uniformly increasing the surface roughness Ra of the inner wall surface 36 of the vortex flow path 24, the increase in pressure loss in the vortex flow path 24 can be suppressed. Therefore, it is possible to effectively suppress the erosion of the turbine blade 18 caused by engine combustion residue while simultaneously suppressing the increase in pressure loss in the vortex flow path 24.

[0067] Furthermore, according to the inventors of this application, the diameter of the particles that have a significant impact on the erosion of the moving blade 18 is about 50 μm. By setting the surface roughness Ra of the inner surface 36i to 25 μm or more, the effect of miniaturizing the particles generated by friction with the inner surface 36i can be improved, thereby effectively suppressing the erosion of the moving blade 18 of the turbine 6.

[0068] In addition, according to Figure 5 The gas casing shown, because the vortex flow path 26 is curved in such a way that its extension line L2a does not intersect with the moving blade 18 of the turbine 6, allows coarse particles contained in the exhaust gas, such as... Figure 5 As shown by arrow a2, the particles collide with the inner wall surface 38 of the vortex flow path 26 before colliding with the moving blade 18. Furthermore, according to the inventors' understanding, even if the coarse particles that collide with the inner wall surface 38 of the vortex flow path 26 flow downstream, their impact on the erosion of the moving blade 18 is limited. Therefore, it is possible to suppress the direct collision between coarse particles in the exhaust gas flowing into the vortex flow path 26 and the moving blade 18 of the turbine 6, thereby suppressing the erosion of the moving blade 18 of the turbine 6.

[0069] Furthermore, since the vortex flow path 24 bends in such a way that its extension line L2a does not intersect with the nozzle blade 12 of the turbine 6, the coarse particles contained in the exhaust gas, such as... Figure 6 As shown by arrow a2, the particles collide with the inner wall surface 38 of the vortex flow path 26 before passing between adjacent nozzle blades 12. Therefore, it is possible to suppress the guidance of coarse particles contained in the exhaust gas from the nozzle blades 12 to the moving blades 18 of the turbine 6, thereby effectively suppressing the erosion of the moving blades 18 of the turbine 6.

[0070] Furthermore, the surface roughness Ra of the inner face 38i is greater than that of the outer face 38o, so particles that collide with the inner face 38i are easily refined through friction with the inner face 38i as they flow downstream. Additionally, compared to uniformly increasing the surface roughness Ra of the inner wall surface 38 of the vortex flow path 26, the increase in pressure loss in the vortex flow path 26 can be suppressed. Therefore, it is possible to effectively suppress the erosion of the turbine blade 18 caused by engine combustion residue while simultaneously suppressing the increase in pressure loss in the vortex flow path 26.

[0071] Furthermore, according to the inventors of this application, the diameter of the particles that have a significant impact on the erosion of the moving blade 18 is about 50 μm. By setting the surface roughness Ra of the inner surface 38i to 25 μm or more, the effect of miniaturizing the particles generated by friction with the inner surface 38i can be improved, thereby effectively suppressing the erosion of the moving blade 18 of the turbine 6.

[0072] In several embodiments, the outwardly facing portion 36° of the aforementioned vortex flow path 24 is, for example, as...Figure 7 As shown, it may also include a protrusion 40 that projects radially outward. That is, the outer portion 36o of the aforementioned vortex flow path 24 may also include a protrusion 40 that projects inward toward the inner portion 36i. In the illustrated example, in the cross-section orthogonal to the axial direction in the turbine 6, the protrusion 40 is formed in a triangular shape. Furthermore, the protrusion 40 is located upstream of the front end position Q1 of the tongue portion 25.

[0073] Furthermore, when the flow path width in the direction orthogonal to the axial direction at the position of the protrusion 40 in the vortex flow path 24 is set to W1, the protrusion 40 has a height h1 that is more than 20% of the flow path width W1. In the illustrated example, the flow path width W1 is the flow path width in the direction orthogonal to the axial direction at the position of the front end of the protrusion 40 in the vortex flow path 24.

[0074] By providing the protrusion 40 at the outward 36°, compared to the case without the protrusion 40, as... Figure 6 As indicated by arrow a1, particles can collide with a position further upstream on the inner wall surface 36 of the vortex flow path 24, thereby promoting particle miniaturization by increasing the time and distance at which they receive frictional forces from the inner wall surface 36. Therefore, erosion of the moving blade 18 can be effectively suppressed. Furthermore, by setting the height h1 of the protrusion 40 to 20% or more of the flow path width W1, the effect of promoting particle miniaturization can be improved compared to setting it to less than 20% of the flow path width W1.

[0075] In several embodiments, the outwardly facing portion 38o of the aforementioned vortex flow path 26 is, for example, as... Figure 7 As shown, it may also include a protrusion 42 that projects radially outward. That is, the outer portion 38o of the aforementioned vortex flow path 26 may also include a protrusion 42 that projects inward toward the inner portion 38i. In the illustrated example, in the cross-section orthogonal to the axial direction in the turbine 6, the protrusion 42 is formed in a triangular shape. Furthermore, the protrusion 42 is located upstream of the front end position Q2 of the tongue portion 32.

[0076] Furthermore, when the flow path width in the direction orthogonal to the axial direction at the location of the protrusion 42 in the vortex flow path 26 is set to W2, the protrusion 42 has a height h2 that is more than 20% of the flow path width W2. In the illustrated example, the flow path width W2 is the flow path width in the direction orthogonal to the axial direction at the location of the front end of the protrusion 42 in the vortex flow path 26.

[0077] By providing the protrusion 42 at the outwardly facing 38°, compared to the case without the protrusion 42, as... Figure 9AAs indicated by the arrow a2, it is possible to cause the particles to collide with a position on the inner wall surface 38 of the swirl flow passage 26 on the more upstream side, and it is possible to promote the refinement of the particles by increasing the time and distance of receiving the frictional force from the inner wall surface 38. Thus, it is possible to effectively suppress the erosion of the vane 18. In addition, by setting the height h2 of the protrusion portion 42 to be 20% or more of the flow passage width W2, as compared with the case where it is set to be less than 20% of the flow passage width W2, it is possible to improve the effect of promoting the refinement of the particles.

[0078] Figure 2 is shown for the turbine 6 shown in Figure 8 is shown for the turbine 6 shown in Figure 9B is shown for the turbine 6 shown in Figure 2 is shown for the turbine 6 shown in Figure 8 is shown for the turbine 6 shown in Figure 9C is shown for the turbine 6 shown in Figure 2 is shown for the turbine 6 shown in Figure 8 is shown for the turbine 6 shown in Figure 9A is shown for the turbine 6 shown in

[0079] In several embodiments, as shown in Figure 9B , the linear flow passage portion 28 of the swirl flow passage 24 includes a circular flow passage cross section. In addition, as shown in Figure 9C and Figure 9B , the swirl flow passage portion 30 of the swirl flow passage 24 includes a flow passage cross section in which the flow passage height H in the axial direction is larger than the flow passage width W in the direction orthogonal to the axial direction (the flow passage width direction orthogonal to the axial direction and the extension direction of the swirl flow passage 24, respectively).

[0080] In the examples shown in Figure 9C and Figure 9B , the swirl flow passage portion 30 of the swirl flow passage 24 includes an elliptical flow passage cross section so that the flow passage height H in the axial direction is larger than the flow passage width W in the direction orthogonal to the axial direction. In the example shown in the drawing, the major axis of the elliptical flow passage cross section extends in the axial direction, and the minor axis of the elliptical flow passage cross section extends in the direction orthogonal to the axial direction. It can also be that the major axis of the elliptical flow passage cross section extends in parallel to the axial direction, and the minor axis of the elliptical flow passage cross section extends in the direction orthogonal to the axial direction.

[0081] Further, the flow path cross section of the scroll flow path 24 can be formed in an elliptical shape in the entire range of the linear flow path portion 28 so that the flow path height H in the axial direction is larger than the flow path width W in the direction orthogonal to the axial direction in the entire range of the scroll flow path portion 30.

[0082] Further, as shown in Figs. 1 and 2, the scroll flow path 24 can be formed so that the ratio H / W of the flow path height H in the axial direction to the flow path width W in the direction orthogonal to the axial direction becomes larger toward the downstream side in the scroll flow path portion 30. Figure 9C and Figure 9A Further, as shown in Figs. 1 and 2, the scroll flow path 24 can be formed so that the ratio H / W of the flow path height H in the axial direction to the flow path width W in the direction orthogonal to the axial direction becomes larger toward the downstream side in the scroll flow path portion 30.

[0083] As described above, by making the flow path height H in the axial direction larger than the flow path width W in the scroll flow path portion 30 of the scroll flow path 24, the contribution of the portion in which the particles collide with the inner wall surface 36 of the scroll flow path 24 can be increased, the refinement of the particles by the friction between the inner wall surface 36 of the scroll flow path 24 and the particles can be promoted, and the erosion of the blades 18 of the turbine 6 can be effectively reduced.

[0084] Further, by forming the scroll flow path 24 so that the ratio H / W of the flow path height H in the axial direction to the flow path width W in the direction orthogonal to the axial direction becomes larger toward the downstream side in the scroll flow path portion 30, the refinement of the particles by the friction between the inner wall surface 36 of the scroll flow path 24 and the particles can be promoted while suppressing an increase in pressure loss caused by a change in flow path shape.

[0085] In several embodiments, as shown in Figs. 1 and 2, the linear flow path portion 33 of the scroll flow path 26 includes a circular flow path cross section. Further, as shown in Figs. 1 and 2, the scroll flow path portion 34 of the scroll flow path 26 includes a flow path cross section in which the flow path height H in the axial direction is larger than the flow path width W in the direction orthogonal to the axial direction (the flow path width direction orthogonal to the axial direction and the extension direction of the scroll flow path 26, respectively). Figure 9B Figure 9C Figure 9B In the example shown in Figs. 1 and 2, the scroll flow path portion 34 of the scroll flow path 26 includes an elliptical flow path cross section in which the flow path height H in the axial direction is larger than the flow path width W in the direction orthogonal to the axial direction. In the example shown in the figures, the major axis of the elliptical flow path cross section extends in the axial direction, and the minor axis of the elliptical flow path cross section extends in the direction orthogonal to the axial direction. Alternatively, the major axis of the elliptical flow path cross section can extend in parallel with the axial direction, and the minor axis of the elliptical flow path cross section can extend in the direction orthogonal to the axial direction. Figure 9C Figure 9A

[0086] Further, as shown in Figs. 1 and 2, the scroll flow path 24 can be formed so that the ratio H / W of the flow path height H in the axial direction to the flow path width W in the direction orthogonal to the axial direction becomes larger toward the downstream side in the scroll flow path portion 30. Figure 9B Figure 9C and​​​​​Figure 9B As shown, it can also be formed into an ellipse so that the axial flow path height H in the entire range of the vortex flow path section 34 is larger than the flow path width W in the direction orthogonal to the axial direction.

[0087] In addition, such as Figure 9C and Figure 10A As shown, the vortex flow path 26 can also be formed such that the ratio H / W of the axial flow path height H and the flow path width W in the direction orthogonal to the axial direction increases toward the downstream side of the vortex flow path section 34.

[0088] As described above, by making the axial flow path height H greater than the flow path width W in the flow path cross section of the vortex flow path 34 in the vortex flow path 26, the contribution of the particle collision portion in the inner wall surface 38 of the vortex flow path 26 can be increased, promoting the miniaturization of particles generated by the friction between the inner wall surface 38 of the vortex flow path 26 and the particles, and effectively reducing the erosion of the moving blade 18 of the turbine 6.

[0089] Furthermore, by forming the vortex flow path 26 such that the ratio H / W of the axial flow path height H and the flow path width W in the direction orthogonal to the axial direction increases toward the downstream side of the vortex flow path section 34, it is possible to suppress the increase in pressure loss caused by the change in flow path shape while promoting the miniaturization of particles generated by the friction between the inner wall surface 38 of the vortex flow path 26 and the particles.

[0090] Figure 2 It is aimed at Figure 8 The turbine 6 shown is shown Figure 10B Schematic diagrams of another example of section A1-A1 and another example of section A2-A2 shown. Figure 2 It is aimed at Figure 8 The turbine 6 shown is shown Figure 10C Schematic diagrams of another example of section B1-B1 and another example of section B2-B2 shown. Figure 2 It is aimed at Figure 8 The turbine 6 shown is shown Figure 10A Schematic diagrams of another example of section C1-C1 and another example of section C2-C2 are shown. Sections A1-A1, B1-B1, and C1-C1 schematically show the flow path sections in vortex flow path 24 that are orthogonal to the extension direction of vortex flow path 24. Sections A2-A2, B2-B2, and C2-C2 schematically show the flow path sections in vortex flow path 26 that are orthogonal to the extension direction of vortex flow path 26.

[0091] In several implementations, such as Figure 10B As shown, the straight flow path portion 28 of the vortex flow path 24 includes a circular flow path cross-section. Additionally, as... Figure 10C and Figure 10BAs shown, the scroll flow path portion 30 of the scroll flow path 24 includes a flow path cross section in which a flow path height H in the axial direction is larger than a flow path width W in a direction orthogonal to the axial direction (a direction orthogonal to the axial direction and the extending direction of the scroll flow path 24, respectively). In Figure 10C and Figure 10A In the example shown, the scroll flow path portion 30 of the scroll flow path 24 includes a flow path cross section that is rectangular (rectangular) such that the flow path height H in the axial direction is larger than the flow path width W in the direction orthogonal to the axial direction. In the example shown, the long side in the rectangular flow path cross section extends along the axial direction, and the short side in the rectangular flow path cross section extends along the direction orthogonal to the axial direction. Alternatively, the long side in the rectangular flow path cross section can extend in parallel to the axial direction, and the short side in the rectangular flow path cross section can extend along the direction orthogonal to the axial direction.

[0092] Further, as shown in Figure 10B and Figure 10C and Figure 10B Alternatively, the scroll flow path 24 can be formed such that the flow path height H in the axial direction is larger than the flow path width W in the direction orthogonal to the axial direction in the entire range of the scroll flow path portion 30.

[0093] Further, as shown in Figure 10C and Figure 10A Alternatively, the scroll flow path 24 can be formed such that the ratio H / W of the flow path height H in the axial direction and the flow path width W in the direction orthogonal to the axial direction increases as it goes toward the downstream side in the scroll flow path portion 30.

[0094] As described above, by making the flow path height H in the axial direction larger than the flow path width W in the flow path cross section of the scroll flow path portion 30 in the scroll flow path 24, the contribution of the portion in which the particles collide in the inner wall surface 36 of the scroll flow path 24 can be increased, the refinement of the particles due to the friction between the inner wall surface 36 of the scroll flow path 24 and the particles can be promoted, and the erosion of the blades 18 of the turbine 6 can be effectively reduced.

[0095] Further, by forming the scroll flow path 24 such that the ratio H / W of the flow path height H in the axial direction and the flow path width W in the direction orthogonal to the axial direction increases as it goes toward the downstream side in the scroll flow path portion 30, the refinement of the particles due to the friction between the inner wall surface 36 of the scroll flow path 24 and the particles can be promoted while suppressing an increase in pressure loss due to a change in flow path shape.

[0096] In several embodiments, as shown in Figure 10B the linear flow path portion 33 of the scroll flow path 26 includes a flow path cross section that is circular. Further, as shown in Figure 10C and Figure 10BAs shown, the scroll flow path portion 34 of the scroll flow path 26 includes a flow path cross section in which the flow path height h in the axial direction is larger than the flow path width W in the direction orthogonal to the axial direction (the direction orthogonal to the axial direction and the extending direction of the scroll flow path 26, respectively). In Figure 10C and Figure 10A In the example shown, the scroll flow path portion 34 of the scroll flow path 26 includes a rectangular flow path cross section in which the flow path height h in the axial direction is larger than the flow path width W in the direction orthogonal to the axial direction. In the example shown, the long side in the rectangular flow path cross section extends along the axial direction, and the short side in the rectangular flow path cross section extends along the direction orthogonal to the axial direction. Alternatively, the long side in the rectangular flow path cross section can extend in parallel to the axial direction, and the short side in the rectangular flow path cross section can extend along the direction orthogonal to the axial direction.

[0097] Further, as shown in Figure 10B and Figure 10C and Figure 10B Further, as shown in

[0098] Further, as shown in Figure 10C and ​ Further, as shown in

[0099] As described above, by making the flow path height H in the axial direction larger than the flow path width W in the flow path cross section of the scroll flow path portion 34 in the scroll flow path 26, it is possible to increase the contribution degree of the portion in which the particles collide with the inner wall surface 38 of the scroll flow path 26, promote the refinement of the particles due to the friction between the inner wall surface 38 of the scroll flow path 26 and the particles, and effectively reduce the erosion of the blade 18 of the turbine 6.

[0100] Further, by forming the scroll flow path 26 in such a manner that the ratio H / W of the flow path height H in the axial direction and the flow path width W in the direction orthogonal to the axial direction increases toward the downstream side in the scroll flow path portion 34, it is possible to promote the refinement of the particles due to the friction between the inner wall surface 38 of the scroll flow path 26 and the particles while suppressing an increase in pressure loss caused by a change in flow path shape.

[0101] The present disclosure is not limited to the above-described embodiments, and includes modes in which the above-described embodiments are modified and modes in which the above-described embodiments are appropriately combined.

[0102] The content described in each of the above-described embodiments is grasped, for example, as follows.

[0103] (1) A supercharger gas casing of at least one embodiment of the present disclosure is a supercharger gas casing (e.g., the gas casing 14 described above) of a turbine (e.g., the turbine 6 described above) of a supercharger (e.g., the supercharger 2 described above), in which

[0104] The supercharger gas casing has a scroll portion (e.g., the scroll portion 23 described above) that forms a plurality of scroll flow passages (e.g., the scroll flow passages 24 and 26 described above) at the same position in the axial direction of the turbine,

[0105] The plurality of scroll flow passages include a first scroll flow passage (e.g., the scroll flow passage 24 or 26 described above),

[0106] The first scroll flow passage is configured such that, in a cross section of the turbine orthogonal to the axial direction, an extension line (e.g., the extension line L1a or L2a described above) of a line segment that connects a position (e.g., the position P1 or P2 described above) farthest from a rotation axis of the turbine at an inlet (e.g., the inlet 24a or 26a described above) of exhaust gas of the first scroll flow passage and a position (e.g., the position Q1 or Q2 described above) of a leading end of a tongue portion formed on an inner peripheral side of the first scroll flow passage does not cross a moving blade (e.g., the moving blade 18 described above) of the turbine.

[0107] According to the supercharger gas casing described in (1) above, since the first scroll flow passage is configured in such a manner that the extension line described above does not cross the moving blade of the turbine, coarse particles contained in the exhaust gas collide with an inner wall surface of the first scroll flow passage before colliding with the moving blade. In addition, according to the present inventor's insight, it is believed that the coarse particles after colliding with the inner wall surface of the first scroll flow passage have limited impact on erosion of the moving blade even if they flow downstream thereafter. Therefore, it is possible to suppress the coarse particles contained in the exhaust gas flowing into the first scroll flow passage from colliding directly with the moving blade of the turbine, thereby suppressing erosion of the moving blade of the turbine.

[0108] (2) In several embodiments, on the basis of the supercharger gas casing described in (1) above,

[0109] The first scroll flow passage is configured such that a nozzle vane (e.g., the nozzle vane 12 described above) that guides flow toward the moving blade in the turbine does not cross the extension line.

[0110] According to the supercharger gas casing described in (2) above, coarse particles contained in the exhaust gas collide with the inner wall surface of the first scroll flow passage before passing between nozzle vanes adjacent to each other. Therefore, it is possible to suppress the coarse particles contained in the exhaust gas from being guided by the nozzle vanes toward the moving blade of the turbine, effectively suppressing erosion of the moving blade of the turbine.

[0111] (3) In several embodiments, on the basis of the supercharger gas casing described in (1) or (2) above,

[0112] The inner wall surface of the first scroll flow path (e.g., the inner wall surface 36 or 38 described above) includes:

[0113] an outward-facing portion (e.g., the outward-facing portion 36o or 38o described above) that faces outward in the radial direction of the turbine; and

[0114] an inward-facing portion (e.g., the inward-facing portion 36i or 38i described above) that faces inward in the radial direction of the turbine, and the surface roughness Ra of the inward-facing portion is greater than the surface roughness Ra of the outward-facing portion.

[0115] According to the supercharger gas casing described in (3) above, the surface roughness Ra of the inward-facing portion is greater than the surface roughness of the outward-facing portion, so particles that have collided with the inward-facing portion are easily micronized by friction with the inward-facing portion as they flow downstream. In addition, compared to a case in which the surface roughness of the inner wall surface of the first scroll flow path is increased as a whole, it is possible to suppress an increase in pressure loss in the first scroll flow path. Thus, it is possible to suppress an increase in pressure loss in the first scroll flow path while effectively suppressing erosion of the turbine blades caused by engine combustion residue.

[0116] (4) In several embodiments, on the basis of the supercharger gas casing described in (3) above,

[0117] The surface roughness Ra of the inward-facing portion is 25 μm or greater.

[0118] According to the inventor's insight, it is believed that particles that have a diameter of about 50 μm have a large impact on erosion of the turbine blades, and by making the surface roughness Ra of the inward-facing portion 25 μm or greater as described in (4) above, it is possible to improve the effect of micronization of particles that occurs by friction with the inward-facing portion, thereby effectively suppressing erosion of the turbine blades.

[0119] (5) In several embodiments, on the basis of the supercharger gas casing described in any one of (1) to (4) above,

[0120] The inner wall surface of the first scroll flow path (e.g., the inner wall surface 36 or 38 described above) includes:

[0121] an outward-facing portion (e.g., the outward-facing portion 36o or 38o described above) that faces outward in the radial direction of the turbine; and

[0122] an inward-facing portion (e.g., the inward-facing portion 36i or 38i described above) that faces inward in the radial direction of the turbine,

[0123] The outward-facing surface includes a protruding portion (e.g., the protruding portions 40 or 42 described above) that protrudes toward the outer side in the radial direction.

[0124] The supercharger gas casing according to the above (5) can cause particles to collide with a position further upstream in the inner wall surface of the first scroll flow path compared to a case where there is no protruding portion, and can promote the refinement of particles by increasing the time and distance of receiving friction from the inner wall surface. Thus, erosion of the vane can be effectively suppressed.

[0125] (6) In some embodiments, the supercharger gas casing according to the above (5) is further characterized in that

[0126] The protruding portion is located at a position upstream of the position of the tip of the tongue portion.

[0127] The supercharger gas casing according to the above (6) can cause particles to collide with a position further upstream in the inner wall surface of the first scroll flow path compared to a case where there is no protruding portion at a position upstream of the position of the tip of the tongue portion, and can promote the refinement of particles by increasing the time and distance of receiving friction from the inner wall surface. Thus, erosion of the vane can be effectively suppressed.

[0128] (7) In some embodiments, the supercharger gas casing according to the above (5) or (6) is further characterized in that

[0129] The protruding portion has a height (e.g., the height h1 or h2 described above) of 20% or more of the flow path width (e.g., the flow path width W1 or W2 described above) in the direction orthogonal to the axial direction in the first scroll flow path.

[0130] The supercharger gas casing according to the above (7) can improve the effect of promoting the refinement of particles compared to a case where the height of the protruding portion is less than 20% of the flow path width in the direction orthogonal to the axial direction in the first scroll flow path.

[0131] (8) In some embodiments, the supercharger gas casing according to any one of the above (1) to (7) is further characterized in that

[0132] The first scroll flow path includes a flow path cross section in which the flow path height (e.g., the flow path height H described above) in the axial direction is greater than the flow path width (e.g., the flow path width W described above) in the direction orthogonal to the axial direction.

[0133] The supercharger gas casing according to (8) above, by making the axial flow path height larger than the flow path width in the flow path cross section of the first scroll flow path, can increase the contribution degree of the portion in which the particles collide in the inner wall surface of the first scroll flow path, promote the refinement of the particles generated by the friction of the inner wall surface of the first scroll flow path and the particles, and effectively reduce the erosion of the turbine moving blade.

[0134] (9) In several embodiments, on the basis of the supercharger gas casing according to (8) above,

[0135] The shape of the flow path cross section is elliptical or rectangular.

[0136] The supercharger gas casing according to (9) above, can obtain the effect according to (8) above with a simple shape.

[0137] (10) The supercharger according to at least one embodiment of the present disclosure has:

[0138] The supercharger gas casing according to any one of (1) to (9) above;

[0139] A turbine working wheel (for example, the turbine working wheel 10 described above); and

[0140] A compressor impeller (for example, the compressor impeller 8 described above) linked to the turbine working wheel via a rotation shaft.

[0141] The supercharger according to (10) above, since it has the supercharger casing according to any one of (1) to (9) above, can suppress the erosion of the turbine moving blade and improve the reliability of the supercharger.

[0142] Explanation of Reference Signs:

[0143] 2 Supercharger

[0144] 4 Compressor

[0145] 6 Turbine

[0146] 8 Compressor Impeller

[0147] 9 Rotation Shaft

[0148] 10 Turbine Working Wheel

[0149] 12 Nozzle Blade

[0150] 14 Gas Casing

[0151] 16 Hub

[0152] 18 Moving Blade

[0153] 20 Working Wheel Housing

[0154] 22 Nozzle Passage Part

[0155] 23 swirl portion

[0156] 24 first swirl flow path

[0157] 24a inlet

[0158] 25 tongue portion

[0159] 26 second swirl flow path

[0160] 26a inlet

[0161] 28 linear flow path portion

[0162] 30 swirl flow path portion

[0163] 32 tongue portion

[0164] 33 linear flow path portion

[0165] 34 swirl flow path portion

[0166] 36 inner wall surface

[0167] 36i inward-facing surface portion

[0168] 36o outward-facing surface portion

[0169] 38 inner wall surface

[0170] 38i inward-facing surface portion

[0171] 38o outward-facing surface portion

[0172] 40 protrusion portion

[0173] 42 protrusion portion

Claims

1. A supercharger gas casing that is a supercharger gas casing of a turbine of a supercharger, wherein the supercharger gas casing has a scroll portion that forms a plurality of scroll flow paths at the same position in an axial direction of the turbine, the plurality of scroll flow paths include a first scroll flow path, the first scroll flow path is configured so that, in a cross section of the turbine that is orthogonal to the axial direction, an extension line of a line segment that connects a position farthest from a rotational axis of the turbine at an inlet of exhaust gas of the first scroll flow path and a position of a front end of a tongue portion formed on an inner peripheral side of the first scroll flow path does not intersect with a blade of the turbine, the first scroll flow path includes a first scroll flow path portion that extends along a circumferential direction of the turbine, the first scroll flow path is formed so that a ratio H / W of a flow path height H in the axial direction and a flow path width W in a direction orthogonal to the axial direction increases toward a downstream side in the first scroll flow path portion.

2. The supercharger gas casing according to claim 1, wherein the first scroll flow path is configured so that a nozzle blade that guides flow toward the blade in the turbine does not cross the extension line.

3. A supercharger gas casing that is a supercharger gas casing of a turbine of a supercharger, wherein the supercharger gas casing has a scroll portion that forms a plurality of scroll flow paths at the same position in an axial direction of the turbine, the plurality of scroll flow paths include a first scroll flow path, the first scroll flow path is configured so that, in a cross section of the turbine that is orthogonal to the axial direction, an extension line of a line segment that connects a position farthest from a rotational axis of the turbine at an inlet of exhaust gas of the first scroll flow path and a position of a front end of a tongue portion formed on an inner peripheral side of the first scroll flow path does not intersect with a blade of the turbine, an inner wall surface of the first scroll flow path includes: an outward facing portion that faces an outer side in a radial direction of the turbine; and an inward facing portion that faces an inner side in the radial direction of the turbine, and a surface roughness Ra of the inward facing portion is greater than a surface roughness Ra of the outward facing portion.

4. The supercharger gas casing according to claim 3, wherein the surface roughness Ra of the inward facing portion is 25 μm or more.

5. The supercharger gas casing according to any one of claims 1 to 4, wherein an inner wall surface of the first scroll flow path includes: an outward facing portion that faces an outer side in a radial direction of the turbine; and an inward facing portion that faces an inner side in the radial direction of the turbine, the outward facing portion includes a protruding portion that protrudes toward the outer side in the radial direction.

6. The supercharger gas casing according to claim 5, wherein the protruding portion is located at a position upstream of the position of the front end of the tongue portion.

7. The supercharger gas casing according to claim 5, wherein the protruding portion has a height that is 20% or more of a flow path width in a direction orthogonal to the axial direction in the first scroll flow path.

8. The supercharger gas casing according to any one of claims 1 to 4, wherein the first scroll flow path includes a flow path cross section in which a flow path height in the axial direction is greater than a flow path height in a direction orthogonal to the axial direction.

9. The supercharger gas casing according to claim 8, wherein a shape of the flow path section is an elliptical shape or a rectangular shape.

10. A supercharger, wherein the supercharger is provided with: the supercharger gas casing according to any one of claims 1 to 9; a turbine working wheel; and a compressor impeller linked to the turbine working wheel via a rotation shaft.

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