Flow matched combined exhaust plenum

Abstract

The present application relates to the technical field of aircraft engine nozzle, and discloses a combined exhaust casing with flow matching, which comprises an exhaust casing body and a center cone arranged in a nozzle; flow guide vane cascades are evenly installed between the inner wall of the exhaust casing body and the outer wall of the center cone; the outer wall of the center cone, the inner wall of the exhaust casing body and two adjacent flow guide vane cascades form an inner-duct exhaust passage; the inner-duct exhaust passage comprises contraction-dilation flow channels and contraction flow channels distributed at intervals; and the outer wall of the exhaust casing body and the nozzle form an outer-duct exhaust passage. The present application can realize efficient mixing of inner-duct airflow and outer-duct airflow at the end of the exhaust casing body, can obtain the inner-duct high-pressure flow of the engine at a stable speed, and can ensure that the inner-duct high-pressure flow is not affected by the change of the outer-duct flow; the problem that the change of the outer-duct flow causes the follow-up change of the inner-duct flow is avoided, the accurate design of the inner-duct high-pressure flow is ensured, and the accurate matching of the high-pressure flow and the low-pressure flow of the engine nozzle is met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aircraft engine nozzle, and discloses a combined exhaust chamber with flow matching. BACKGROUND

[0002] With the development of the aviation industry, in order to pursue the highest economic use of the aircraft, the economic applicability of the engine is improved.

[0003] The traditional exhaust chamber and mixer scheme has the shortcomings that the high-pressure flow in the inner channel is easily affected by the change of the flow in the outer channel, and requires a large exhaust space, so that the high-pressure flow in the inner channel cannot be accurately designed in a compact space, and the purpose of accurately controlling the core engine state cannot be met. SUMMARY

[0004] The present application aims to provide a combined exhaust chamber with flow matching, which can realize efficient mixing of the inner channel flow and the outer channel flow at the end of the exhaust chamber body, can obtain the high-pressure flow in the inner channel of the engine at a stable speed, and the high-pressure flow in the inner channel is not affected by the change of the flow in the outer channel; the problem that the change of the flow in the outer channel causes the change of the flow in the inner channel is avoided, the accurate design of the high-pressure flow in the inner channel is ensured, and the accurate matching of the high-pressure and low-pressure flow of the engine nozzle is met.

[0005] In order to achieve the above technical effects, the technical scheme adopted by the present application is as follows:

[0006] A combined exhaust chamber with flow matching, comprising an exhaust chamber body and a center cone coaxially arranged in a nozzle; a guide vane cascade is uniformly installed between the inner wall of the exhaust chamber body and the outer wall of the center cone in a ring shape, the outer wall of the center cone, the inner wall of the exhaust chamber body and the adjacent two guide vanes form an annular and uniformly distributed inner channel exhaust passage, the inner channel exhaust passage comprises a contraction and expansion flow passage and a contraction flow passage which are distributed at intervals, wherein the contraction and expansion flow passage is formed by the outer wall of the center cone, the adjacent two guide vanes and a contraction and expansion wall assembly arranged on the inner wall of the exhaust chamber body; the contraction flow passage is formed by the outer wall of the center cone, the adjacent two guide vanes and a contraction wall assembly arranged at the tail of the exhaust chamber body; the outer wall of the exhaust chamber body and the nozzle form an outer channel exhaust passage.

[0007] Further, the contraction and expansion wall assembly comprises a first contraction section and a first expansion section, the included angle between the first contraction section and the central axis of the center cone ranges from 10° to 30°, and the included angle between the first expansion section and the central axis of the center cone is less than or equal to 28°.

[0008] Further, the second expansion section is arranged at the tail of the exhaust manifold body corresponding to the converging-diverging flow channel, and the included angle between the second expansion section and the central cone central axis is greater than or equal to 2° and less than or equal to 5°.

[0009] Further, the second converging section is arranged at the tail of the exhaust manifold body corresponding to the converging flow channel, and the included angle between the second converging section and the central cone central axis ranges from 11° to 26°.

[0010] Further, the boss structure is arranged on the central cone surface corresponding to the converging-diverging flow channel, and the boss structure is smoothly connected from the tail of the converging-diverging flow channel to the central position of the central cone.

[0011] Further, the central cone has a smaller taper angle at the position corresponding to the converging flow channel than the included angle between the second converging section and the central cone central axis.

[0012] Further, the guide vane cascade includes a pre-rotation section and a straight section, and the straight section is located at the end of the guide vane cascade in the airflow direction.

[0013] Compared with the prior art, the present application has the beneficial effects that: the inner content high-pressure airflow in the present application can realize efficient mixing of the inner content airflow and the outer content airflow at the end of the exhaust manifold body due to the control of the cross section of the guide vane cascade, the converging-diverging flow channel and the converging flow channel, the inner content high-pressure flow can be obtained while the engine is at a stable speed, the inner content high-pressure flow is not affected by the change of the outer content flow, the problem that the change of the outer content flow causes the follow-up change of the inner content flow is avoided, the accurate design of the inner content high-pressure flow is ensured, and the precise matching of the high-pressure flow and the low-pressure flow of the engine nozzle is further met. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 The figure is a schematic view of the combined exhaust manifold structure for the flow matching in the embodiment;

[0015] Figure 2 The figure is a schematic view of the combined exhaust manifold structure for the flow matching in the embodiment; Figure 1 The figure is an enlarged schematic view of the local part A in the embodiment;

[0016] Figure 3 The figure is an enlarged schematic view of the local part B in the embodiment; Figure 1 The figure is an enlarged schematic view of the local part B in the embodiment;

[0017] Figure 4 The figure is a schematic view of the structure of the guide vane cascade pre-rotation section and the straight section in the embodiment;

[0018] Figure 5 The figure is a schematic view of the structure of the guide vane cascade pre-rotation section and the straight section in the embodiment;

[0019] 1, nozzle; 2, exhaust duct body; 3, center cone; 4, guide vane cascade; 5, inner bypass exhaust passage; 6, outer bypass exhaust passage; 7, first contraction section; 8, first expansion section; 9, second expansion section; 10, second contraction section; 11, boss structure; 12, pre-rotation section; 13, straight section. DETAILED DESCRIPTION

[0020] The application will be further described below in connection with the embodiments and drawings. However, it should not be understood that the above-mentioned subject matter of the application is limited to the following embodiments only, and any technology realized based on the content of the application falls within the scope of the application.

[0021] EMBODIMENT

[0022] Reference Figures 1-5 A flow-matched combined exhaust duct includes an exhaust duct body 2 and a center cone 3 coaxially arranged in a nozzle 1. A guide vane cascade 4 is uniformly installed between the inner wall of the exhaust duct body 2 and the outer wall of the center cone 3. The outer wall of the center cone 3, the inner wall of the exhaust duct body 2, and two adjacent guide vanes 4 form an annular and uniformly distributed inner bypass exhaust passage 5. The inner bypass exhaust passage 5 includes contraction-expansion flow passages and contraction flow passages which are distributed at intervals. The contraction-expansion flow passage is formed by the outer wall of the center cone 3, two adjacent guide vanes 4, and a contraction-expansion wall assembly arranged on the inner wall of the exhaust duct body 2. The contraction flow passage is formed by the outer wall of the center cone 3, two adjacent guide vanes 4, and a contraction wall assembly arranged at the tail of the exhaust duct body 2. The outer wall of the exhaust duct body 2 and the nozzle 1 form an outer bypass exhaust passage 6.

[0023] In the embodiment, the inner-cone exhaust passage 5 is designed as a contraction-diffusion flow channel and a contraction flow channel, so that the inner-cone high-pressure airflow is divided into two streams, one of which is discharged through the contraction-diffusion flow channel, and the other is discharged through the contraction flow channel. The contraction-diffusion flow channel and the contraction flow channel can also divide the airflow in the outer-cone exhaust passage 6 into two streams. The two streams of the inner-cone exhaust passage 5 and the two streams of the outer-cone exhaust passage 6 are mixed alternately in the annular cavity corresponding to the inner wall of the nozzle 1 and the center cone 3, and are finally discharged from the outlet of the nozzle 1. When the engine is at a stable speed, the airflow entering the inner-cone exhaust passage 5 is at a subsonic speed. After passing through the contraction part of the contraction-diffusion flow channel and the contraction flow channel, the airflow in the flow channel is accelerated to the speed of sound. Since the area of the flow channel is fixed, when the inner-cone high-pressure airflow is accelerated to the speed of sound, the inner-cone exhaust passage 5 generates a throttling effect, and the flow rate remains basically unchanged and is not affected by downstream disturbances. In the embodiment, the inner-cone high-pressure flow of the engine at a stable speed is obtained by controlling the cross section of the guide vane cascade 4, the contraction-diffusion flow channel, and the contraction flow channel. Moreover, the inner-cone high-pressure flow is not affected by the change of the outer-cone flow. Compared with the traditional mixer, the change of the outer-cone flow does not cause the change of the inner-cone flow, so that the inner-cone high-pressure flow can be accurately designed, and the matching of the high-pressure flow and the low-pressure flow can be accurately designed. In particular, the nozzle 1 can have a large duct flow capacity in a compact space, and can meet the requirements of high-altitude, long-endurance, and low-fuel consumption of the whole machine.

[0024] In the embodiment, the speed of the airflow entering the inner-cone flow channel is controlled by designing the twist angle of the guide vane cascade 4, the distance between the guide vane cascades 4, and the contraction angle of the contraction-diffusion flow channel. The speed of the airflow entering the inner-cone flow channel reaches the speed of sound. In the embodiment, the contraction-diffusion wall assembly includes a first contraction section 7 and a first expansion section 8. The included angle between the first contraction section 7 and the central axis of the center cone 3 is in the range of 10° to 30°. The included angle between the first expansion section 8 and the central axis of the center cone 3 is less than or equal to 28°. The tail part of the exhaust casing body 2 corresponding to the contraction-diffusion flow channel is provided with a second expansion section 9. The included angle between the second expansion section 9 and the central axis of the center cone 3 is greater than or equal to 2° and less than or equal to 5°. The tail part of the exhaust casing body 2 corresponding to the contraction flow channel is provided with a second contraction section 10. The included angle between the second contraction section 10 and the central axis of the center cone 3 is in the range of 11° to 26°.

[0025] The boss structure 11 is arranged on the center cone 3 cone surface corresponding to the converging-diverging flow passage, and the boss structure 11 is smoothly connected from the tail of the converging-diverging flow passage to the middle position of the center cone 3. By arranging the wedge-shaped boss structure 11 extending to the middle position of the center cone 3 at the end of the converging-diverging flow passage, the gas flow out of the end of the converging-diverging flow passage can be smoothly flowed to the surface of the center cone 3, which can ensure that the inner and outer flow gas is mixed at a large area at the end of the converging-diverging flow passage, and the disturbance or vortex at the transition position of the converging-diverging flow passage and the center cone 3 can be avoided, and the total pressure loss of the outer flow gas caused by the too large expansion angle of the flow passage can be reduced.

[0026] The center cone 3 has a smaller cone surface angle at the position corresponding to the converging flow passage than the included angle between the second converging section 10 and the central axis of the center cone 3. This is beneficial to the efficient mixing of the gas flow of the outer flow passage and the gas flow out of the tail of the converging flow passage, and can ensure that the inner flow gas sprayed from the converging flow passage and the center cone 3 do not have too much separation.

[0027] The guide vane cascade 4 in the embodiment includes a pre-rotation section 12 and a straight section 13 located at the end in the gas flow direction of the guide vane cascade 4. The pre-rotation section 12 is designed in terms of twist angle and cascade spacing according to the required gas flow velocity, so as to meet the inner flow gas velocity requirement, and the straight section 13 is located at the end in the gas flow direction of the guide vane cascade 4, which ensures that the sprayed gas flow is straight and non-rotating, and the sprayed gas flow will not cause the exhaust gas casing body 2 to produce a rotating moment.

[0028] The above is only a preferred embodiment of the present application, and is not used to limit the present application, any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A flow-matching combined exhaust casing, characterized in that, The system includes an exhaust casing body (2) and a central cone (3) coaxially disposed within the nozzle (1); guide vanes (4) are uniformly installed circumferentially between the inner wall of the exhaust casing body (2) and the outer wall of the central cone (3); the outer wall of the central cone (3), the inner wall of the exhaust casing body (2), and two adjacent guide vanes (4) together form an annularly distributed inner exhaust channel (5); the inner exhaust channel (5) includes a contraction-expansion channel and a contraction channel distributed at intervals; the contraction-expansion channel is formed by the outer wall of the central cone (3), two adjacent guide vanes (4), and a contraction-expansion wall assembly disposed on the inner wall of the exhaust casing body (2); the contraction channel is formed by the outer wall of the central cone (3), two adjacent guide vanes (4), and a contraction wall assembly disposed at the tail of the exhaust casing body (2); the outer wall of the exhaust casing body (2) and the nozzle (1) form an outer bypass exhaust channel (6).

2. The combined exhaust casing with flow matching according to claim 1, characterized in that, The shrinking and expanding wall assembly includes a first shrinking section (7) and a first expanding section (8). The angle between the first shrinking section (7) and the central axis of the central cone (3) is in the range of 10° to 30°. The angle between the first expanding section (8) and the central axis of the central cone (3) is less than or equal to 28°.

3. The combined exhaust casing with flow matching according to claim 1, characterized in that, The exhaust casing body (2) corresponding to the contraction and expansion flow channel is provided with a second expansion section (9) at the tail end. The angle between the second expansion section (9) and the central axis of the central cone (3) is greater than or equal to 2° and less than or equal to 5°.

4. The combined exhaust casing with flow matching according to claim 3, characterized in that, The exhaust casing body (2) corresponding to the contraction channel is provided with a second contraction section (10) at the tail end, and the angle between the second contraction section (10) and the central axis of the central cone (3) is in the range of 11° to 26°.

5. The combined exhaust casing with flow matching according to claim 4, characterized in that, A boss structure (11) is provided on the cone surface of the central cone (3) corresponding to the contraction and expansion channel. The boss structure (11) is smoothly connected from the tail of the contraction and expansion channel to the middle position of the central cone (3).

6. The combined exhaust casing with flow matching according to claim 4, characterized in that, The angle of the cone surface of the central cone (3) at the position corresponding to the contraction channel is less than the angle between the second contraction section (10) and the central axis of the central cone (3).

7. The combined exhaust casing with flow matching according to claim 1, characterized in that, The guide vane (4) includes a pre-swirl section (12) and a straight section (13), the straight section (13) being located at the end of the airflow direction of the guide vane (4).

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