Centripetal turbine, aircraft engine and method of use

Abstract

The application relates to the technical field of turbine blades, in particular to a centripetal turbine, an aero-engine and a use method. The centripetal turbine comprises turbine guide vanes, the turbine guide vanes comprise a guide vane hub and at least two guide vanes, the at least two guide vanes are arranged in a circumferential array on the guide vane hub, each of the guide vanes is respectively provided with a shock wave weakening tail edge, and the shock wave weakening tail edge is used for weakening the shock wave intensity blowing to the guide vanes. The application provides the centripetal turbine, the aero-engine and the use method, so as to solve the problem that the shock wave pulsation load is overlapped with the blade inherent frequency, high-cycle fatigue failure is easily caused, and the service life of the blade is shortened.

Description

Technical Field

[0001] This invention relates to the field of turbine blade technology, specifically to a centripetal turbine, an aero-engine, and a method of using it. Background Technology

[0002] As a highly efficient energy conversion device, the radial turbine is widely used in small-flow aero-engines, gas turbines, and internal combustion engine turbochargers due to its compact structure, small size, large single-stage enthalpy drop, and high expansion ratio. Currently, with the continuous advancement of high-load turbine design, the expansion ratio requirement for advanced single-stage radial turbines has reached over 5.0, and its internal airflow is gradually entering the transonic operating range, while the guide vanes and moving blades are developing towards full supersonic speeds.

[0003] Under normal operating conditions, the centripetal turbine guide vanes achieve subsonic stable expansion through a gradually narrowing flow channel. When the expansion ratio exceeds a critical threshold, the airflow accelerates to a transonic state, and the discontinuity in curvature at the guide vane trailing edge causes a severe deflection of the flow direction, forming a shock wave. Studies have shown that under small turbine opening conditions, the proportion of leakage flow increases, and it mixes with the mainstream to form leakage vortices, changing the local flow angle and further inducing asymmetric shock wave distribution.

[0004] In actual use of the impeller, shock wave pulsation loads will overlap with the natural frequency of the blades, which can easily lead to high-cycle fatigue failure and thus shorten the service life of the blades. Summary of the Invention

[0005] This invention provides a centripetal turbine, an aero-engine, and a method of use to solve the problem that shock wave pulsation loads overlap with the natural frequency of the blades, easily causing high-cycle fatigue failure and shortening the blade's service life.

[0006] In a first aspect, the present invention provides a centripetal turbine, comprising: A turbine guide vane, comprising a guide vane hub and at least two guide vanes, wherein the at least two guide vanes are arranged in a circumferential array on the guide vane hub, and each guide vane is provided with a shock wave weakening trailing edge, wherein the shock wave weakening trailing edge weakens the intensity of the shock wave blowing toward the guide vane.

[0007] By setting a shock wave weakening trailing edge on the guide vane, the intensity of the shock wave blowing on the guide vane is weakened by the shock wave weakening trailing edge, so that the strong shock wave formed by the transonic airflow at the trailing edge of the guide vane is transformed into several weak shock waves. This avoids the overlap of shock wave pulsation load with the natural frequency of the blade, improves aerodynamic efficiency, prevents high-cycle fatigue failure, reduces blade creep damage, and thus extends the service life of the turbine blade.

[0008] In one alternative implementation, each of the guide vanes has a trailing edge, and the shock wave weakening trailing edge is disposed close to the trailing edge.

[0009] In one alternative implementation, each of the shock wave attenuation trailing edges includes at least two attenuation segments, which are arranged in parallel to each other.

[0010] In one alternative embodiment, the guide vane includes a pressure surface, and the shock wave weakening trailing edge connects the pressure surface and the trailing edge.

[0011] In one alternative implementation, the shock wave attenuation trailing edge further includes at least two transition sections, the transition sections connecting adjacent attenuation sections, or the transition sections connecting adjacent pressure surfaces and attenuation sections.

[0012] In one optional embodiment, the guide vane further includes a leading edge and a suction surface, wherein one side of the leading edge and the trailing edge is the pressure surface, and the other side of the leading edge and the trailing edge is the suction surface.

[0013] In one alternative implementation, the transition segment is a circular arc, an elliptical curve, or a sine curve.

[0014] Secondly, the present invention also provides an aircraft engine, including the aforementioned radial turbine.

[0015] In one alternative embodiment, the system further includes a volute having a tapered flow channel within which the working fluid flows toward the centripetal turbine.

[0016] Thirdly, the present invention also provides a method of using a centripetal turbine, wherein the shock wave weakens the trailing edge to reduce the intensity of the shock wave blowing toward the guide vanes. Attached Figure Description

[0017] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 This is an exploded schematic diagram of the volute, turbine guide vanes, and rotor impeller according to an embodiment of the present invention; Figure 2 This is a schematic diagram of a turbine guide vane according to an embodiment of the present invention; Figure 3 This is a schematic diagram of a turbine guide vane in which the transition section of the shock wave weakening trailing edge is a circular arc curve, according to an embodiment of the present invention. Figure 4 This is a schematic diagram of a turbine guide vane in which the transition section of the shock wave weakening trailing edge is an elliptical curve, according to an embodiment of the present invention. Figure 5 This is a schematic diagram of a turbine guide vane in which the transition section of the shock wave attenuation trailing edge is a sine curve, according to an embodiment of the present invention. Figure 6 This is a schematic diagram of the engagement of two turbine guide vanes according to an embodiment of the present invention.

[0019] Explanation of reference numerals in the attached drawings: 1. Volute; 2. Guide vane hub; 3. Guide vane; 301. Suction surface; 302. Pressure surface; 303. Leading edge; 304. Trailing edge; 305. Shock wave weakening trailing edge; 3051. Weakening section; 3052. Transition section; 4. Rotor impeller. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] The following is combined with Figures 1 to 6 The following describes embodiments of the present invention.

[0022] According to an embodiment of the present invention, in one aspect, a centripetal turbine is provided, comprising: The turbine guide vane includes a guide vane hub 2 and at least two guide vanes 3. The at least two guide vanes 3 are arranged in a circumferential array on the guide vane hub 2. Each guide vane 3 is provided with a shock wave weakening trailing edge 305, which weakens the intensity of the shock wave blowing on the guide vane 3.

[0023] By setting a shock wave weakening trailing edge 305 on the guide vane 3, the shock wave intensity blowing onto the guide vane 3 is weakened by the shock wave weakening trailing edge 305, so that the strong shock wave formed by the transonic airflow at the trailing edge of the guide vane is transformed into several weak shock waves. This avoids the overlap of shock wave pulsation load and the natural frequency of the blade, improves aerodynamic efficiency, prevents high-cycle fatigue failure, reduces blade creep damage, and thus extends the service life of the turbine blade. It should be noted that the guide vane hub 2 is annular, that is, at least two guide vanes 3 are arranged in a circumferential array with the central axis of the guide vane hub 2 as the center of symmetry.

[0024] In one embodiment, such as Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, each guide vane 3 has a trailing edge 304, and a shock wave weakening trailing edge 305 is disposed near the trailing edge 304 to weaken the shock wave at the trailing edge 304.

[0025] In one embodiment, such as Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, each shock wave weakening trailing edge 305 includes at least two weakening segments 3051, which are arranged in parallel with adjacent weakening segments 3051. The arrangement of at least two weakening segments 3051 achieves step-by-step deflection, redirecting the airflow blowing onto the guide vanes 3, causing the original shock wave to generate multiple weak oblique shock waves. The shock wave pulsation capability is absorbed by the multi-stage weakening segments 3051, thereby achieving the purpose of weakening the shock wave intensity. It should be noted that in this embodiment, the number of weakening segments 3051 is three.

[0026] In one embodiment, such as Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, the guide vane 3 includes a pressure surface 302 and a shock wave attenuating trailing edge 305 connecting the pressure surface 302 and the trailing edge 304. The pressure surface 302 guides the airflow to the shock wave attenuating trailing edge 305, where it is attenuated. In this embodiment, as... Figure 1 , Figure 6 As shown, the pressure surface 302 can be configured as a convex curve or a concave curve to facilitate guiding the pressure to the shock wave attenuation trailing edge 305.

[0027] In one embodiment, such as Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, the shock wave attenuation trailing edge 305 further includes at least two transition segments 3052. The transition segments 3052 connect adjacent attenuation segments 3051, or connect adjacent pressure surfaces 302 and attenuation segments 3051, to form the shock wave attenuation trailing edge 305. It should be noted that in this embodiment, the transition segments 3052 smoothly transition to the pressure surfaces 302 and attenuation segments 3051, and the connection points are tangential.

[0028] In one embodiment, such as Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 and Figure 6As shown, the guide vane 3 also includes a leading edge 303 and a suction surface 301. One side of the leading edge 303 and the trailing edge 304 is a pressure surface 302, and the other side of the leading edge 303 and the trailing edge 304 is a suction surface 301. That is, the pressure surface 302 of one guide vane 3 is used to guide the airflow to the shock wave weakening trailing edge 305. The weakened weak oblique shock wave bounces onto the suction surface 301 of another guide vane 3, and is further bounced and dispersed by the suction surface 301.

[0029] In this embodiment, as Figure 2 As shown, the distance *a* from the starting position of the shock wave weakening trailing edge 305 to the leading edge 303, and the distance *b* from the starting position of the shock wave weakening trailing edge 305 to the trailing edge 304, are given. The distance between the leading edge 303 and the trailing edge 304 is *s* = *a* + *b*, where *a* = 0.9~0.95s. The specific position can be determined according to the guide vane design and operating conditions. Typically, the shock wave weakening trailing edge 305 is located at the position where the shock wave is generated on the pressure surface 302. In this application, *a* = 0.95s. Based on the actual flow conditions of the shock wave weakening trailing edge 305, the deflection angle α of the shock wave weakening trailing edge 305 is... i (The deflection angle refers to the angle between the tangents at the two junctions of the transition segment 3052) ranges from 2° to 10°. In addition, the length range of the weakening segment 3051 in this embodiment (the sum of the lengths of all weakening segments 3051 of the shock wave weakening trailing edge 305) is 0.1 to 0.4b.

[0030] In one embodiment, such as Figure 1 , Figure 2 , Figure 3 As shown, the transition section 3052 is a circular arc curve. The circular arc curve will not interfere with the airflow and can also guide the airflow.

[0031] According to an embodiment of the present invention, another aspect provides an aircraft engine including the aforementioned radial turbine.

[0032] In one embodiment, such as Figure 1 As shown, it also includes a volute 1, which has a tapered flow channel. The working fluid flowing in the tapered flow channel is blown toward the centripetal turbine. Specifically, the working fluid is air.

[0033] In this embodiment, as Figure 1 As shown, it also includes a rotor impeller 4. Both the rotor impeller 4 and the turbine guide vane are annular, and the rotor impeller 4 and the turbine guide vane are arranged on the same central axis. The turbine guide vane is provided with an annular through hole, and the rotor impeller 4 is located in the through hole. During use, the turbine guide vane remains stationary while the rotor impeller 4 moves.

[0034] According to an embodiment of the present invention, another aspect provides a method for using a centripetal turbine: a high-temperature and high-pressure working fluid (gas) is uniformly distributed through the spiral flow channel of the volute 1 to the guide vane flow channel provided towards the turbine guide vane. The guide vane flow channel is tapered. The working fluid expands in the guide vane flow channel, and the pressure energy is converted into kinetic energy, increasing the airflow speed. When passing through the throat of the guide vane flow channel, the airflow reaches the transonic speed stage. The shock wave weakening trailing edge 305 forms a multi-stage flow direction deflection and progressively compresses the airflow at the trailing edge 304, generating multiple weak oblique shock waves. The shock wave pulsation energy is absorbed by the multi-stage weakening section 3051, thereby achieving the purpose of reducing the shock wave intensity.

[0035] The centripetal turbine provided by the present invention has the following advantages: (1) By setting a shock wave weakening trailing edge 305 on the guide vane 3, the shock wave intensity blowing on the guide vane 3 is weakened by the shock wave weakening trailing edge 305, so that a strong shock wave formed by the transonic airflow at the trailing edge of the guide vane is transformed into several weak shock waves, avoiding the overlap of shock wave pulsation load and the natural frequency of the blade, improving aerodynamic efficiency, preventing high-cycle fatigue failure, reducing the creep damage of the blade, and thus extending the service life of the turbine blade; (2) the transonic airflow passes through the shock wave weakening trailing edge 305. When the weak trailing edge 305 is formed, the multi-stage flow direction deflection is formed due to the setting of the multi-stage weakening section 3051, and the airflow is compressed step by step, which decomposes the single strong shock wave into multiple weak shock waves; (3) Compared with the traditional guide vane, the weak shock wave interacts with the step-induced vortex, reduces the turbulent kinetic energy dissipation, reduces the wake loss, and improves the aerodynamic efficiency; (4) The shock wave intensity in the flow channel is weakened, the aerodynamic load of the turbine guide vane trailing edge 304 and the rotor blade leading edge 303 is reduced, high cycle fatigue failure is prevented, and the blade service life is improved.

[0036] As an alternative implementation, the number of weakening segments 3051 in this application may also be 2, 4, 5 or even more.

[0037] As an alternative implementation, the transition section 3052 can also be an elliptic curve ( Figure 4 (as shown) or sine curve ( Figure 5 (As shown).

[0038] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A centripetal turbine, characterized in that, include: The turbine guide vane includes a guide vane hub (2) and at least two guide vanes (3). The at least two guide vanes (3) are arranged in a circumferential array on the guide vane hub (2). Each guide vane (3) is provided with a shock wave weakening trailing edge (305) to weaken the intensity of the shock wave blowing toward the guide vane (3).

2. The centripetal turbine according to claim 1, characterized in that, Each of the guide vanes (3) has a trailing edge (304), and the shock wave weakening trailing edge (305) is located close to the trailing edge (304).

3. The centripetal turbine according to claim 2, characterized in that, Each of the shock wave attenuation trailing edge (305) includes at least two attenuation segments (3051), which are arranged in parallel with each other.

4. The centripetal turbine according to claim 3, characterized in that, The guide vane (3) includes a pressure surface (302), and the shock wave weakening trailing edge (305) connects the pressure surface (302) and the trailing edge (304).

5. The centripetal turbine according to claim 4, characterized in that, The shock wave attenuation trailing edge (305) further includes at least two transition segments (3052), which connect adjacent attenuation segments (3051), or the transition segments (3052) connect adjacent pressure surfaces (302) and attenuation segments (3051).

6. The centripetal turbine according to claim 4, characterized in that, The guide vane (3) also includes a leading edge (303) and a suction surface (301). One side of the leading edge (303) and the trailing edge (304) is the pressure surface (302), and the other side of the leading edge (303) and the trailing edge (304) is the suction surface (301).

7. The centripetal turbine according to claim 5, characterized in that, The transition section (3052) is a circular arc curve, an elliptical curve, or a sine curve.

8. An aircraft engine, characterized in that, Includes the centripetal turbine as described in any one of claims 1-7.

9. The aero-engine according to claim 8, characterized in that, It also includes a volute (1) with a tapered flow channel inside, and the working fluid flowing in the tapered flow channel is blown toward the centripetal turbine.

10. A method of using a centripetal turbine, for using the centripetal turbine of claim 1, characterized in that, The shock wave weakens the trailing edge (305) to reduce the intensity of the shock wave blowing toward the guide vane (3).

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