Turbine inlet housing of an axial turbine of a turbocharger
The turbine inlet housing with axially inclined ribs addresses cracking and relative movement issues, improving thermal stability and operational reliability.
Patent Information
- Authority / Receiving Office
- DE · DE
- Patent Type
- Patents
- Current Assignee / Owner
- EVERLLENCE SE
- Filing Date
- 2017-08-04
- Publication Date
- 2026-06-25
AI Technical Summary
Turbine inlet casings in turbochargers are susceptible to cracking and relative movement due to thermal cycling, reducing their service life and affecting operational stability.
A turbine inlet housing design featuring axially inclined ribs with a teardrop-shaped cross-section, minimizing thermal stress and relative movement, and enhancing thermal stability.
The design reduces crack formation and propagation, enhances thermal endurance, and maintains operational stability by minimizing relative movement between components.
Smart Images
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Abstract
Description
The invention relates to a turbine inlet housing of an axial turbine of a turbocharger. A turbocharger comprises a turbine for expanding a first medium and a compressor for compressing a second medium. The turbocharger's turbine has a turbine housing and a turbine rotor. The turbocharger's compressor has a compressor housing and a compressor rotor. The turbine rotor and the compressor rotor are connected to each other via a shaft, which is rotatably mounted in a bearing housing of the turbocharger. The bearing housing of the turbocharger is connected to both the turbine housing and the compressor housing. The turbine of a turbocharger can be designed as an axial turbine or a radial turbine. Likewise, the compressor of a turbocharger can be designed as an axial compressor or a radial compressor. The present invention relates to a turbine inlet housing of the turbine housing of a turbine of a turbocharger designed as an axial turbine. The basic structure of an axial turbine of a turbocharger is known from DE 20 2014 002 981 U1. This prior art document shows, in part, the turbine rotor of the turbine together with the turbine inlet housing of the turbine casing. DE 20 2014 002 981 U1 shows the flow outlet end of the turbine inlet housing, at which the turbine inlet housing, namely a radially inner wall and a radially outer wall thereof, defines an annular flow channel in cross-section. The medium to be depressurized can be supplied to the turbine rotor of the axial turbine via this annular flow channel. According to DE 20 2014 002 981 U1, a nozzle ring is positioned between the turbine rotor and the flow-outlet end of the turbine inlet casing. The nozzle ring is also referred to as a guide vane or guide grid. CN 201 090 252 Y discloses a turbine inlet housing of an axial turbine of a turbocharger according to the preamble of claim 1. US 2012 / 0 045 320 A1 and JP 2000 - 328 906 A reveal further state of the art. It is known from practice that the radially inner wall of the turbine inlet housing and its radially outer wall are connected to each other by ribs that extend through the annular flow channel at the flow outlet end of the turbine inlet housing. These ribs are exposed to the flow of the medium that is to be supplied to the turbine rotor. Turbine inlet casings known from practical experience are susceptible to cracking due to thermal cycling. This reduces the service life of the turbine inlet casing. In addition to cracking, turbine inlet casings known from practical experience also suffer from the problem that relative movement can develop between the turbine inlet casing and a component mounted on it, particularly the guide vane or nozzle ring, also as a result of thermal cycling. This movement then alters the gaps established between the turbine inlet casing and the guide vane during operation. There is a need for a turbine inlet casing that is less susceptible to cracking due to thermal cycling. Furthermore, there is a need to minimize relative movement between the turbine inlet casing and a component mounted on it that develops as a result of thermal cycling.Based on this, the present invention aims to create a novel turbine inlet housing. This problem is solved by a turbine inlet housing according to claim 1. The invention reduces the risk of cracking in the turbine inlet housing. Furthermore, it minimizes the risk of relative movement between the turbine inlet housing and a component mounted on it. The turbine inlet housing according to the invention can withstand a large number of thermal load cycles. Preferred embodiments of the invention are described in the dependent claims and the following description. Exemplary embodiments of the invention are explained in more detail with reference to the drawing, without being limited thereto. Figure 1 shows an axial section through a turbine inlet housing according to the invention for an axial turbine of a turbocharger. Fig. 1 shows a turbine inlet housing 10 of an axial turbine of a turbocharger. Such a turbine inlet housing 10 has a flow-inlet end with a flow-inlet flange 11 and a flow-outlet end with a flow-outlet flange 12. At the inlet end, the medium, which is to be expanded in the region of the axial turbine, enters the turbine inlet casing 10. At the outlet end, this medium exits the turbine inlet casing 10 in the axial direction and is then fed axially to a turbine rotor of the axial turbine. The outlet direction of the medium at the outlet end 12 is therefore axial to the axial direction of the axial turbine. For this reason, the section through the turbine inlet casing 10 shown in Fig. 1 is also referred to as an axial section. The turbine inlet housing 10 has an outer wall 13 and an inner wall 14. At the flow-inlet end of the turbine inlet housing 10, the outer wall 13 defines an inlet flow channel 15 with a circular cross-section. At the flow-outlet end, the outer wall 13, together with the inner wall 14, defines an outlet flow channel 16 with an annular cross-section. At the flow-inlet end, the circular flow channel 15 is defined by the outer wall 13, and at the flow-outlet end, the annular flow channel 16 is defined by the outer wall 13 and the inner wall 14. The inner wall 14 is also referred to as the bell. Ribs 15 extend between the outer wall 13 and the inner wall 14, with the inner wall 14 being connected to the outer wall 13 via ribs 17. The ribs 17 run within the flow channel between the annular, outlet-side flow channel 16 and the circular, inlet-side flow channel 15. The medium flowing through the turbine inlet housing 10 flows around the ribs 17. The ribs 17, exposed to the medium flow, have an upstream side 21, an outstream side 20, and flow-guiding surfaces 18, 19 extending between the outstream side 20 and the upstream side 21. The connecting sections 22 of the ribs 17, with which the ribs 17 engage the outer wall 13 of the turbine inlet housing 10, are positioned in the region of the flow-inlet-side flange 11 and extend into the region of the flow-inlet-side flange 11. Thus, the connecting section 22 of the ribs on the outer wall 13 is displaced into the region of the flow-inlet-side end and therefore of the flow-inlet-side flange 11 of the turbine inlet housing 10. The connecting section 26 of the ribs 17, via which the ribs 17 attack the inner wall 14, is positioned closer to the flow outlet side end of the turbine inlet housing 10 than to the flow inlet side end of the turbine inlet housing. The ribs 17 are axially inclined relative to a radial direction 23 in the axial section of Fig. 1, such that a longitudinal center axis 24 of the respective ribs 17 forms an angle α with the radial direction 23, which is between 45° and 85°, preferably between 60° and 80°, and particularly preferably between 60° and 70°. As a result, the ribs 17 have a relatively small height and thus a relatively small radial extent when viewed in the radial direction. These features increase the thermal stability and thus the service life of the turbine inlet housing 10. The risk of crack formation in the area of the fins 17 is reduced. Furthermore, crack propagation behavior is minimized. The risk of relative movement between the turbine inlet housing and a component mounted on the turbine inlet housing is also reduced. The ribs 17 have a teardrop-shaped cross-section (see Detail II of Fig. 1, which shows cross-section II-II). The ribs 17 are preferably contoured in such a way that the flow-guiding surfaces 18, 19 of the ribs 17 initially diverge from the upstream side 21 towards inflection points 25 of the teardrop-shaped contoured surfaces 18, 19 and subsequently converge from these inflection points 25 towards the downstream side 20, the distance of the inflection points 25 from the downstream side 20 being greater than from the upstream side 21. The inflection points 25 are those points on the flow-guiding surfaces 18, 19 at which their diverging course transitions into their converging course. This provides a particularly advantageous flow pattern in the area of the ribs 17, in particular the flow downstream of the ribs 17 is gently merged. Shading effects are minimized. It is provided that a ratio d / l between the distance of the flow-guiding surfaces 18, 19 in the area of the turning points 25 and the distance I between the upstream side 21 and the downstream side 20 is greater than 0.4 and less than 1.0, preferably greater than 0.5 and less than 0.9, and particularly preferably greater than 0.6 and less than 0.8. When the ribs 17 are characterized by such a d / I ratio, they exhibit a significant thickening, thereby increasing the thermal stability and thus the service life of the turbine inlet housing 10. The risk of crack formation in the area of the ribs 17 is reduced. Furthermore, crack propagation behavior is minimized. The risk of relative movement between the turbine inlet housing and an assembly mounted on the turbine inlet housing is also reduced. The present invention therefore proposes a novel turbine inlet housing 10 for an axial turbine of a turbocharger. The invention serves to reduce the risk of crack formation due to thermal load cycles. Furthermore, minimized crack propagation behavior can be achieved. The turbine inlet housing 10 can withstand a large number of thermal load cycles. There is no risk of relative movement between the turbine inlet housing and any assembly mounted on it. Furthermore, homogeneous flow guidance can be provided without the risk of vibration excitation for a downstream guide vane. Reference symbol list 10 Turbine inlet housing 11 Flow inlet flange 12 Flow outlet flange 13 Outer wall 14 Inner wall 15 Circular inlet flow channel 16 Annular outlet flow channel 17 Rib 18 Flow-guiding surface 19 Flow-guiding surface 20 Downstream side 21 Upstream side 22 Connection section 23 Radial direction 24 Longitudinal center axis 25 Inflection point 26 Connection section
Claims
Turbine inlet housing (10) of an axial turbine of a turbocharger, with a flow-inlet-side flange (11) at a flow-inlet-side end, at which an outer wall (13) of the turbine inlet housing (10) defines an inlet flow channel (15) with a circular cross-section, with a flow-outlet-side flange (12) at a flow-outlet-side end, at which the outer wall (13) of the turbine inlet housing (10) and an inner wall (14) of the same define an annular cross-section outlet flow channel (16), with ribs (17) by means of which the outer wall (13) of the turbine inlet housing (10) and the inner wall (14) of the same are connected to each other, wherein connection sections (22) of the ribs (17), with which they engage the outer wall (13) of the turbine inlet housing (10), at least are positioned section by section in the area of the flow inlet-side flange (11), characterized in thatthat the ribs (17) have a teardrop-shaped cross-section, flow-guiding surfaces (18, 19) of the ribs (17), which extend between an upstream side (21) and an downstream side (20) of the respective rib (17) and between the outer wall (13) and the inner wall (14), initially diverge from the upstream side (21) towards inflection points (25) of the rib contour and subsequently converge from the inflection points (25) towards the downstream side, wherein a ratio d / l between the distance d of the flow-guiding surfaces (18, 19) in the region of the inflection points (25) and the distance l between the upstream side (21) and downstream side (20) is greater than 0.4 and less than 1.
0. Turbine inlet housing (10) according to claim 1, characterized in that the connecting sections (22) of the ribs (17), with which they engage the outer wall (13) of the turbine inlet housing (10), extend to the flow inlet side flange (11). Turbine inlet housing (10) according to claim 1 or 2, characterized in that the ribs (17) are axially inclined relative to a radial direction (23) when viewed in an axial section. Turbine inlet housing (10) according to claim 3, characterized in that, viewed in axial section, a longitudinal central axis (24) of the respective rib (17) forms an angle (α) between 45° and 85° with the radial direction (23). Turbine inlet housing (10) according to claim 4, characterized in that, viewed in axial section, the longitudinal center axis (24) of the respective rib (17) forms an angle (α) between 60° and 80° or between 60° and 70° with the radial direction (23). Turbine inlet housing (10) according to one of claims 1 to 5, characterized in that the flow-guiding surfaces (18, 19) of the ribs (17) define the droplet contour of the ribs (17). Turbine inlet housing (10) according to claim 6, characterized in that the distance of the turning points (25) from the outflow side (20) is greater than from the inflow side (21). Turbine inlet housing (10) according to one of claims 1 to 7, characterized in that the ratio d / I is greater than 0.5 and less than 0.
9. Turbine inlet housing (10) according to one of claims 1 to 7, characterized in that the ratio d / I is greater than 0.6 and less than 0.8.