Compressor stabilizer passage

Abstract

The present invention relates to a stabilizer flow path (10) for a compressor, particularly a radial or diagonal compressor, the stabilizer flow path (10) having an annular stabilizer chamber (12) surrounding a main flow path (13) in the suction area of ​​a compressor wheel (21) and separated from the main flow path (13) by an annular web (14). The annular stabilizer chamber (12) is bladeless and connected via a downstream inlet flow path (15) and an upstream outlet opening (16). A plurality of flow guide elements (17) are arranged in the downstream inlet flow path (15). The downstream inlet flow path (15) is arranged between an upstream portion (141) of the annular web (14) and a downstream portion (142) of the annular web (14). The present invention further relates to a compressor, particularly a radial or diagonal compressor, equipped with the stabilizer flow path (10) according to the present invention, and further to a turbocharger equipped with this compressor.

Description

[Technical field]

[0001] The present invention relates to the field of compressors, particularly radial and diagonal compressors. In particular, the present invention relates to a stabilizer passage at the compressor inlet for increasing the map width and characteristic curve slope of a compressor stage. [Background technology]

[0002] Exhaust gas turbochargers are used to improve the performance of internal combustion engines, in particular reciprocating piston engines, and usually comprise a radial or diagonal compressor and a radial or axial turbine.

[0003] The practical operating range of radial and diagonal compressors is limited towards smaller mass flows by surge limits / flow instabilities, and as the compressor is throttled, the incidence angle becomes increasingly worse until the flows separate and pumping occurs. The allowable incidence angle at which the flow still occurs decreases as the Mach number of the flow increases. That is, the map width tends to decrease for stages with high pressure ratios and / or high suction capacity.

[0004] As a means to stabilize the characteristic curve, a bypass in the form of an annular cavity can be provided in the compressor housing above the wheel profile of the compressor wheel, parallel to the suction passage. Such a bypass is also known as a stabilizer chamber or recirculator. By using a recirculator, the mass flow at the compressor wheel inlet can be artificially increased close to the surge limit. A part of the mass flow is diverted from the compressor wheel to a side chamber (bypass). This mass flow has a high swirl component (in the direction of impeller rotation, co-swirl). This co-swirl reduces the compressor power and leads to a flat characteristic curve close to the surge limit.

[0005] A flat characteristic curve close to the surge limit can cause unexpected pumping in applications with pressure pulsations (e.g. caused by valve movement in supercharged internal combustion engines). For this reason, it is required to provide a minimum pressure rise between the operating point and the surge limit point on the operating speed curve. For stages with high pressure ratios and conventional bypass / stabilizer flow paths, this requirement can hardly be met due to the high power and flat power profile for mass flow at constant speed. Summary of the Invention [Problem to be solved by the invention]

[0006] The object of the present invention is to provide a stabilizer flowpath for a compressor, in particular a radial or diagonal compressor, which is improved with respect to at least one of the drawbacks known in the prior art.Furthermore, the object of the present invention is to provide an improved compressor and an improved turbocharger. [Means for solving the problem]

[0007] To achieve the above object, a stabiliser flowpath for a compressor, in particular a radial or diagonal compressor, is provided according to independent claim 1. Furthermore, a compressor having a stabiliser flowpath according to the embodiments described herein, and a turbocharger comprising such a compressor are provided.

[0008] Further aspects, advantages and features of the present invention are found in the dependent claims, the description and the accompanying drawings.

[0009] According to one aspect of the invention, a stabilizer flowpath of a compressor, in particular a radial or diagonal compressor, is provided. The stabilizer flowpath comprises an annular stabilizer chamber surrounding a main flowpath at a suction area of ​​a compressor wheel and bounded relative to the main flowpath by an annular web. The annular stabilizer chamber is vane-free and connected to a downstream inlet flowpath via an upstream outlet opening. A plurality of flow directing elements are arranged in the downstream inlet flowpath. The downstream inlet flowpath is arranged between an upstream portion of the annular web and a downstream portion of the annular web.

[0010] Thus, a stabilizer flowpath is advantageously provided that allows for increased map width and characteristic curve gradient of a compressor stage. Furthermore, the stabilizer flowpath according to the present invention having a flow directing element in the downstream inlet flowpath provides a stabilizer flowpath that is more advantageous in terms of component integration, storability and manufacturing costs than conventional stabilizers according to the prior art.

[0011] According to a second aspect of the present invention, a compressor, in particular a radial or diagonal compressor, is provided, comprising a compressor wheel and a stabilizer channel according to one of the embodiments described herein, and thus a compressor with increased map width and characteristic curve gradient can be advantageously provided.

[0012] A third aspect of the present invention relates to a turbocharger having a compressor according to one of the embodiments described herein, which advantageously provides an improved turbocharger over the prior art.

[0013] The invention is explained below by means of exemplary embodiments shown in the drawings, from which further advantages and modifications follow. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic diagram of a stabilizer flow path according to the prior art. [Diagram 2] FIG. 2 is a schematic diagram of a stabilizer flow path according to embodiments described herein. [Figure 3a] FIG. 13 is a schematic diagram of a stabilizer flow path according to a further embodiment described herein. [Figure 3b] FIG. 13 is a schematic diagram of a stabilizer flow path according to a further embodiment described herein. [Figure 4a] FIG. 13 is a schematic diagram of a stabilizer flow path according to a further embodiment described herein. [Figure 4b] FIG. 4b is an enlarged view of a detail of FIG. 4a. [Diagram 5] FIG. 13 is a schematic diagram of an inlet flow path of a stabilizer flow path according to a further embodiment described herein. [Figure 6] FIG. 13 is a schematic diagram of an inlet flow path of a stabilizer flow path according to a further embodiment described herein. [Figure 7] 1A-1C are schematic diagrams illustrating configurations of flow directing elements for generating a reverse swirl of a flow as it passes through the flow directing element. [Figure 8] 1A-1C are schematic diagrams illustrating configurations of flow directing elements for reducing swirl of a flow passing through the flow directing element. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Figure 1 is a schematic diagram of a prior art stabilizer flow passage 10. In detail, Figure 1 shows a cross section along the axis of rotation 11 of a compressor wheel 21 through the housing of a radial compressor used to compress air, for example in exhaust gas turbochargers. A stabilizer chamber 12 is arranged in the compressor housing 5. The stabilizer chamber 12 is connected to a main flow passage 13 via an inlet flow passage 15 and an outlet opening 16. The stabilizer chamber 12 is delimited relative to the main flow passage 13 by an annular web 14. A retaining rib 121, which connects the annular web 14 to the compressor housing, is arranged in the stabilizer chamber 12.

[0016] The stabilizer flowpath of a compressor according to the present disclosure is described below with reference to Figures 2 to 8. The compressor may be a radial compressor or a diagonal compressor.

[0017] According to one embodiment, which can be combined with other embodiments described herein, the stabilizer flow path 10 comprises an annular stabilizer chamber 12 surrounding the main flow path 13 in the suction area of ​​the compressor wheel 21. In other words, the stabilizer flow path 10 is typically located at the compressor inlet. It is noted in this context that in the present disclosure, the "stabilizer flow path" is understood to be in particular a flow path at the compressor inlet configured to increase the map width of a compressor stage. For example, the stabilizer flow path 10 can be a recirculation flow path.

[0018] The annular stabilizer chamber 12 is further delimited with respect to the main flow passage 13 by an annular web 14, as exemplarily shown in FIG. 2. The annular stabilizer chamber 12 is vane-free. In other words, no vanes, in particular no flow guide vanes, are arranged in the annular stabilizer chamber 12. In particular, the annular stabilizer chamber 12 can be strut-free. In other words, the annular stabilizer chamber 12 can be flow guide vane-free and strut-free, such that there are no vanes and no struts in the annular stabilizer chamber 12. Furthermore, the annular stabilizer chamber 12 is connected to the main flow passage 13 via a downstream inlet flow passage 15 and an upstream outlet opening 16. The annular stabilizer chamber 12 can be rotationally symmetrical.

[0019] As shown diagrammatically in FIG. 2, the downstream inlet flow passage 15 is provided with a plurality of flow guide elements 17. Typically, the plurality of flow guide elements 17 are arranged circumferentially around the central axis 11 of the main flow passage 13. In particular, the plurality of flow guide elements 17 can be arranged concentrically around the central axis 11 of the main flow passage 13. It is further noted that the flow guide elements 17 can be formed to be flush with the inlet opening 15A on the main flow passage side of the inlet flow passage 15 and / or flush with the outlet opening 15B on the stabilizer chamber side of the inlet flow passage 15. Alternatively, as exemplarily shown in FIG. 2, the flow guide elements 17 can be spaced apart from the inlet opening 15A on the main flow passage side of the inlet flow passage 15 and / or from the outlet opening 15B on the stabilizer chamber side of the inlet flow passage. The downstream inlet flow passage 15 is disposed between an upstream portion 141 of the annular web 14 and a downstream portion 142 of the annular web 14.

[0020] In the present disclosure, the term "inlet flow passage" is understood to mean a flow passage that functions as a flow inlet flow passage to the stabilizer chamber. Typically, the inlet flow passage 15 includes an inlet opening 15A on the main flow passage side and an outlet opening 15B on the stabilizer chamber side, as exemplarily shown in FIG. 2.

[0021] In this disclosure, the terms "downstream" and "upstream" refer to the main flow of the main flow passage of the suction area of ​​the compressor wheel. For better understanding, the main flow passage direction 1 is shown in the figures. According to one embodiment, the inlet flow passage 15 of the stabilizer chamber can be located downstream with respect to the inlet edge 24 of the compressor wheel 21, as shown in Figure 2. The outlet opening 16 of the stabilizer chamber is typically located upstream of the inlet edge 24 of the compressor wheel 21.

[0022] According to one embodiment, which may be combined with other embodiments described herein, the plurality of flow directing elements 17 are configured and arranged to provide a deflection grid through which the flow can pass. For example, the deflection grid may be configured and arranged to provide a deflection grid through which the flow can pass substantially radially. In the present disclosure, the expression "substantially radially" is understood to mean an angular range of less than or equal to α=±45°, in particular less than or equal to α=±25°, relative to the radial direction r. As exemplarily shown in FIG. 2, the radial direction r extends perpendicular to the central axis 11. According to one embodiment, "substantially radially" is understood to mean an angular range of less than or equal to ±10° relative to the radial direction r. For better understanding, FIG. 5 exemplarily shows an inlet channel 15 inclined at an angle α that corresponds to the above-mentioned definition of "substantially radially". The angle α is in the xr plane.

[0023] According to one embodiment, which may be combined with other embodiments described herein, the downstream inlet flow passage 15 extends substantially radially, as exemplarily shown in the embodiment of Figures 2 to 5.

[0024] According to another embodiment, which can be combined with other embodiments described herein, the plurality of flow guiding elements 17 are configured and arranged to provide a deflection grid that can pass substantially axially, as exemplarily shown in Fig. 6. In the present disclosure, the expression "substantially axially" is understood to mean an angular range of ±45° or less, in particular ±25° or less, relative to the axial direction x, as exemplarily shown in Fig. 2, which extends along the central axis 11. According to one embodiment, "substantially axially" is understood to mean an angular range of ±10° or less relative to the axial direction x. A deflection grid that can pass substantially axially can be provided, for example, by a configuration of the inlet channel 15 of the stabilizer chamber according to Fig. 6 and an arrangement of the flow guiding elements 17.

[0025] According to one embodiment, which may be combined with other embodiments described herein, the downstream inlet flow passage 15 comprises a substantially radially extending portion 15C and a substantially axially extending portion 15D, as exemplarily shown in Figure 6. Between the substantially radially extending portion 15C and the substantially axially extending portion 15D there is typically a curved transition region 15F.

[0026] According to one embodiment, which may be combined with other embodiments described herein, the upstream portion 141 of the annular web 14 comprises a substantially radially extending first protrusion 18. The downstream portion 142 of the annular web 14 may also comprise a substantially radially extending second protrusion 19A, as exemplarily shown in Figures 4a, 4b and 5. Alternatively, the downstream portion 142 of the annular web 14 may comprise a substantially axially extending second protrusion 19B, as exemplarily shown in Figure 6.

[0027] According to one embodiment, which can be combined with other embodiments described herein, the stabilizer flowpath 10 is an integral part of the compressor housing, as exemplarily shown in Fig. 2. Alternatively, the stabilizer flowpath 10 can be integrated into an insert 22 that can be attached to the suction area of ​​the compressor, as exemplarily shown in Fig. 3a. According to a further example, the stabilizer flowpath can be part of the inner compressor housing 20A, as exemplarily shown in Fig. 3b, in which a compressor 20 is shown having an inner compressor housing 20A and an outer compressor housing 20B.

[0028] According to one embodiment, which can be combined with other embodiments described herein, the upstream portion 141 of the annular web 14 and the downstream portion 142 of the annular web 14 are connected via a number of flow guiding elements 17, for example by a threaded connection. The threaded connection can extend through the flow guiding elements 17. It should be noted that the threaded connection can also be made in a different way, i.e. so as not to extend through the flow guiding elements 17. Alternatively or additionally, it is also possible to use other types of connection means, such as for example shrinkage or clamps.

[0029] According to one embodiment, which may be combined with other embodiments described herein, the flow directing elements 17 are in the form of separate components. According to another embodiment, which may be combined with other embodiments described herein, the flow directing elements 17 are integrally (in one piece) formed with the upstream portion 141 of the annular web 14 and / or are integrally (in one piece) formed with the downstream portion 142 of the annular web 14.

[0030] According to one embodiment, which can be combined with other embodiments described herein, the downstream portion 142 of the annular web 14 has a centering shoulder 143. Alternatively or additionally, the upstream portion 141 of the annular web 14 can have a centering shoulder (not explicitly shown). The centering shoulder can be cylindrical or conical.

[0031] According to one embodiment, which can be combined with other embodiments described in this specification, each of the multiple flow guiding elements 17 has a centering seat configured to position the flow guiding element 17 circumferentially, in particular concentrically, around the central axis 11 of the main flow passage 13 in the inlet flow passage 15.

[0032] According to one embodiment, which can be combined with other embodiments described herein, at least one, in particular at least half or all of the plurality of flow guiding elements 17 are formed from a Curtis vane profile. In particular, at least one, in particular at least half or all of the plurality of flow guiding elements 17 can be a prismatic Curtis vane. Typically, the flow guiding elements 17 are in the form of radial deflection vanes. Forming the flow guiding elements from a Curtis vane profile, in particular in the form of a prismatic Curtis vane, has the advantage that they can be made relatively thick, so that the upstream portion 141 of the annular web 14 and the downstream portion 142 of the annular web 14 can be better connected via such a guiding element, for example by a threaded connection or other suitable type of connection means.

[0033] According to one embodiment, which can be combined with other embodiments described herein, as exemplarily shown in Figures 4a and 4b, a number of flow guiding elements 17 are arranged in the outlet region of the inlet channel 15 of the stabilizer chamber. The outlet region of the inlet channel 15 is understood to mean the region of the inlet channel 15 located on the side of the outlet opening 15b on the stabilizer chamber side. The outlet region can extend, for example, over half or less of the inlet channel length L. For better understanding, the outlet region 15E of the inlet channel 15 is exemplarily shown in Figure 4b. The arrangement of the flow guiding elements 17 in the outlet region of the inlet channel 15 can have an advantageous effect on the flow velocity and vane vibration excitation.

[0034] According to one embodiment, which can be combined with other embodiments described herein, each of the flow guiding elements 17 has an inlet end 17a and an outlet end 17b, and the outlet ends 17B of each of the flow guiding elements 17 are circumferentially inclined relative to the inlet ends 17A of each of the flow guiding elements 17 so as to reduce swirl as they pass by, as exemplarily shown by the arrows between the inlet ends 17A and the outlet ends 17B in FIG. 8 .

[0035] Alternatively, the outflow end 17B of each of the flow directing elements 17 can be inclined circumferentially with respect to the inflow end 17A of each of the flow directing elements 17 so as to create a counter swirl, as illustrated by the arrow between the inflow end 17A and the outflow end 17B in Figure 7. For better understanding, the rotation direction 2 of the compressor wheel is shown in Figures 7 and 8. The rotation of the compressor wheel causes the flow to be subjected to a swirl.

[0036] According to a second aspect of the disclosure, a compressor, in particular a radial or diagonal compressor, is provided, comprising a compressor wheel 21 and a stabilizer passage 10 according to an embodiment described herein. According to an embodiment, which can be combined with other embodiments described herein, the compressor wheel 21 comprises a number N1 of compressor wheel vanes 23 in the region of the inlet opening 15a. The number N2 of guide elements in the downstream inlet passage 15 is in the relationship N2≧1.5×N1. This is advantageous for reducing the generation of noise and vibration during operation of the compressor.

[0037] A third aspect of the present invention relates to a turbocharger having a compressor according to one of the embodiments described herein, advantageously providing an improved turbocharger over the prior art. [Explanation of symbols]

[0038] 1 Main flow direction 2. Compressor wheel rotation direction 5 Compressor housing 10 Stabilizer Channel 11 Central shaft / Compressor wheel rotation shaft 12 Annular stabilizer chamber 121 Strut 13 Main channel 14 Circular Web 141 Upstream portion of annular web 142 downstream portion of annular web 143 Centering Shoulder 15 Stabilizer chamber inlet passage 15A Inlet opening of the inlet channel on the main channel side 15B Outlet opening of inlet passage on stabilizer chamber side 15C A portion of the inlet passage extending substantially radially 15D A portion of the inlet passage extending substantially axially 15E Outlet area of ​​inlet channel 15F Transition Area 16 Stabilizer chamber outlet opening 17 Flow Guidance Elements 17A Inlet end of flow guide element 17B Outlet end of flow guide element 18 a first protrusion extending substantially in a radial direction 19A second protrusion extending substantially radially 19B a second protrusion extending substantially in the axial direction 20 Compressor 20A Inner Compressor Housing 20B Outer compressor housing 21 Compressor wheel 22 Insertion parts 23 Compressor wheel vanes 24 Compressor wheel inlet edge r radial direction x-axis direction L Inlet passage length α is the angle in the xr plane to describe "substantially radially"

Claims

1. A stabilizer flowpath (10) of a compressor, comprising: The stabilizer flowpath (10) comprises an annular stabilizer chamber (12) surrounding a main flowpath (13) in the suction area of ​​the compressor wheel (21) and bounded relative to the main flowpath (13) by an annular web (14); The annular stabilizer chamber (12) is vane-free and is connected via a downstream inlet passage (15) and an upstream outlet opening (16); A plurality of flow directing elements (17) are disposed in the downstream inlet flow passage (15); the downstream inlet channel (15) is disposed between an upstream portion (141) of the annular web (14) and a downstream portion (142) of the annular web (14); a stabilizer flowpath, wherein an upstream portion (141) of the annular web (14) comprises a first protrusion (18) extending substantially in a radial direction and a downstream portion (142) of the annular web (14) comprises a second protrusion (19A) extending substantially in a radial direction or a downstream portion (142) of the annular web (14) comprises a second protrusion (19B) extending substantially in an axial direction.

2. The stabilizer flowpath of claim 1 , wherein the plurality of flow directing elements (17) are constructed and arranged to provide a passable deflection grid.

3. 3. The stabilizer flowpath of claim 1 or 2, wherein the downstream inlet flowpath (15) extends substantially radially, or the downstream inlet flowpath (15) comprises a substantially radially extending portion (15C) and a substantially axially extending portion (15D).

4. The stabilizer flowpath of any one of claims 1 to 3, wherein the plurality of flow directing elements (17) are arranged circumferentially around a central axis (11) of the main flowpath (13).

5. 5. The stabilizer flowpath according to claim 1, wherein the stabilizer flowpath is an integral part of the compressor housing, or the stabilizer flowpath is incorporated in an insert (22) that can be attached to the suction area of ​​the compressor, or the stabilizer flowpath is part of an inner compressor housing (20A) that constitutes the inside of the housing compressor.

6. 6. The stabilizer flowpath of claim 1, wherein the upstream portion (141) of the annular web (14) and the downstream portion (142) of the annular web (14) are connected via the plurality of flow directing elements (17).

7. The stabilizer flowpath of any one of claims 1 to 6, wherein the plurality of flow directing elements (17) are in the form of separate components.

8. 8. The stabilizer flowpath of claim 1, wherein the plurality of flow directing elements (17) are integrally formed with at least one of the upstream portion (141) of the annular web (14) and the downstream portion (142) of the annular web (14).

9. 9. The stabilizer flowpath of claim 1, wherein at least one of the downstream portion (142) of the annular web (14) and the upstream portion (141) of the annular web (14) comprises a centering shoulder (143).

10. 10. The stabilizer flowpath of claim 1, wherein each of the plurality of flow directing elements (17) has a centering seat configured to position the flow directing element (17) circumferentially within the downstream inlet flowpath (15) about a central axis (11) of the main flowpath (13).

11. The stabilizer flowpath of any of claims 1 to 10, wherein at least one of the plurality of flow directing elements (17) is at least one of a Curtis vane profile, a prismatic vane profile, and a Curtis vane.

12. The stabilizer flowpath of any one of claims 1 to 11, wherein the flow directing elements (17) are arranged in an outlet region (15E) of the downstream inlet flowpath (15) of the annular stabilizer chamber.

13. 13. The stabilizer flowpath of claim 1, wherein each of the flow guiding elements (17) has an inlet end (17A) and an outlet end (17B), the outlet ends of the flow guiding elements (17) being inclined circumferentially relative to the inlet end (17A) so as to reduce swirl or generate reverse swirl as they pass.

14. A compressor (20), comprising a compressor wheel (21) and a stabilizer flowpath (10) according to any one of claims 1 to 13.

15. A turbocharger comprising a compressor (20) according to claim 14.

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