An aviation gas turbine engine

Abstract

The present invention discloses an aviation gas turbine engine, comprising an afterburner, wherein the central cone of the afterburner is composed of a front section, a first connecting section, a middle section, a second connecting section and a rear section connected in sequence, wherein the front section, the middle section and the rear section are made of a high-temperature alloy, wherein the first connecting section and the second connecting section are made of a shape memory alloy, and when the cone surface temperature of the central cone reaches the deformation temperature, the first connecting section and the second connecting section are deformed, and the inclination angles of the front section and the rear section change with the deformation of the first connecting section and the second connecting section, and the cone size of the central cone changes accordingly, and the overall profile posture of the central cone in the afterburner is dynamically adjusted; and air film holes are opened on the front section, the middle section and the rear section. The present invention utilizes the adaptive deformation ability of the memory alloy to change the cone profile of the central cone, dynamically adjusts the spray angle of each section of the air film, changes the flow field distribution and the air film coverage effect, and improves the aerodynamic and thermal performance of the air film cooling of the central cone.

Description

Technical Field

[0001] The present invention relates to the field of aviation engines, and in particular to an aviation gas turbine engine. Background Art

[0002] In the development of aviation gas turbine engines, in order to significantly and quickly increase the engine thrust, the integrated afterburner has been widely studied, especially in military turbojet and turbofan engines. In the new integrated afterburner, the turbine rear support plate and the fuel injection rod are integrated together, and the return vortex formed at the tail of the rear support plate is used to achieve flame stabilization to reduce flow losses and the weight of the engine. However, while the afterburner increases the engine thrust, it also produces high-temperature combustion gas, which greatly increases the heat load of the hot end components. An efficient cooling structure is urgently needed to solve the above problems.

[0003] As an important rectifying and diffuser component of the integrated afterburner, it is crucial to further optimize the aerodynamic and thermal performance of the center cone. The gas temperature above the center cone is close to 2000K, so effective cooling measures must be used to protect the center cone and other core components of the combustion chamber to avoid high temperature corrosion and damage. Summary of the invention

[0004] Purpose of the invention: The present invention aims to provide an aviation gas turbine engine that combines a memory alloy with an air film cooling structure to change the flow field distribution and the air film coverage effect to improve the aerodynamic and thermal performance of air film cooling.

[0005] Technical solution: The aviation gas turbine engine described in the present invention includes an afterburner, and the central cone of the afterburner is composed of a front section, a first connecting section, a middle section, a second connecting section and a rear section connected in sequence, and the front section, the middle section and the rear section are made of high-temperature alloys, and the first connecting section and the second connecting section are made of shape memory alloys. When the cone surface temperature of the central cone reaches the deformation temperature, the first connecting section and the second connecting section are deformed, and the inclination angles of the front section and the rear section change with the deformation of the first connecting section and the second connecting section, and the cone size of the central cone changes accordingly, and the overall surface posture of the central cone in the afterburner is dynamically adjusted; the front section, the middle section and the rear section are all provided with air film holes.

[0006] Furthermore, air film holes are also formed on the first connecting segment and the second connecting segment. When the first connecting segment and the second connecting segment are deformed, the air film holes on the first connecting segment and the second connecting segment change in size accordingly.

[0007] Preferably, the inclination angle of the front section is 40°~60°; the middle section is horizontally arranged, and its inclination angle does not change with the memory alloy; and the inclination angle of the rear section is 20°~30°.

[0008] Furthermore, the shape memory alloy temperature of the first connecting section and the second connecting section T s and dependent variable F The relationship is

[0009] ;

[0010] In the formula ，M f 、M s 、A s and A f Respectively represent the temperatures of the start of martensitic transformation, the end of martensitic transformation, the start of austenitic transformation and the end of austenitic transformation; F max is the maximum deformation of the shape memory alloy. Below the critical design temperature (i.e., the martensitic phase transformation start temperature), the first connecting section and the second connecting section present an initial cambered state; when the temperature exceeds the critical design temperature, the first connecting section and the second connecting section deform, the overall opening direction remains unchanged, but the camber decreases, and the connection presents an extended and stretched state.

[0011] Furthermore, the center angle of the first connecting section is 35°~60°, and the corresponding center is located on the high-temperature mainstream side; the center angle of the second connecting section is 30°~40°, and the corresponding center is located on the cooling secondary flow side.

[0012] Preferably, the air film holes are regularly arranged on the front section, the first connecting section, the middle section, the second connecting section and the rear section to form a stable air film to protect the wall surface.

[0013] Furthermore, after the first connecting segment and the second connecting segment are deformed, the total opening area of ​​the air film holes on the first connecting segment and the second connecting segment increases in the range of 0-10%.

[0014] Preferably, the aperture of each section of the air film holes is greater than or equal to 1.0 mm and less than 1.5 mm, the air film hole row spacing is 10 mm, the air film hole pitch is 6 mm, and the air film holes are all opened in the opposite direction of the high-temperature mainstream.

[0015] Preferably, the deflection angle of the air film hole is determined according to the inclination angles of the front section, the middle section, and the rear section and the position where the backflow vortex appears in the numerical calculation. The deflection angle of the air film hole in the front section is 55°, the deflection angle of the air film hole in the middle section is 45°, and the deflection angle of the air film hole in the rear section is 30°.

[0016] Furthermore, the shape of the air film hole is any one of a reference circular hole, a fan-shaped hole and a convergent slit hole. Preferably, the shape of the air film hole is a reference circular hole. Among the three hole types, the fan-shaped hole has the best overall cooling effect, followed by the reference circular hole. Considering that the fan-shaped hole is a segmented expansion structure, it is difficult to process in actual combustion chamber applications, especially at a maximum aperture of 1-2 mm. Considering the cooling effect and the actual processing difficulty, the present invention preferably uses a reference circular hole.

[0017] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: 1. The present invention adopts a connecting segment made of shape memory alloy to connect the front segment, middle segment and rear segment of the center cone, and utilizes the adaptive deformation ability of the memory alloy to change the cone shape of the center cone, dynamically adjust the blowing angle of each segment of the air film, thereby changing the flow field distribution characteristics and the air film covering effect, and improving the aerodynamic and thermal performance of the center cone air film cooling structure; 2. The present invention adopts a connecting segment made of shape memory alloy with air film holes to replace the original rigid connecting segment without air film holes, further optimizing the covering effect of the cooling air film on the center cone wall, thereby improving the overall thermal performance of the center cone cooling structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the structure of the present invention before the first and second connecting segments are deformed;

[0019] Figure 2 It is a schematic diagram of the structure of the present invention after the first and second connecting segments are deformed;

[0020] Figure 3 A schematic diagram of calculating the area and boundaries of an embodiment;

[0021] Figure 4 A comparison diagram of the average spanwise integrated cooling efficiency of the center cone surface of a rigid connection segment without air film holes and a connection segment with air film holes made of shape memory alloy;

[0022] Figure 5 A comparison chart of the relative pressure loss of the central cone main channel using a rigid air-free film hole connecting section and a connecting section with air film holes made of shape memory alloy. DETAILED DESCRIPTION

[0023] The present invention will be further described below in conjunction with the accompanying drawings.

[0024] The aviation gas turbine engine of the present invention comprises an afterburner, wherein the central cone of the afterburner is composed of a front section 1, a first connecting section 2, a middle section 3, a second connecting section 4 and a rear section 5 connected in sequence, wherein the front section 1, the middle section 3 and the rear section 5 are made of a high-temperature alloy, the first connecting section 2 and the second connecting section 4 are made of a shape memory alloy, the center angle of the first connecting section 2 is 35° to 60°, and the corresponding center is located on the high-temperature mainstream A side; the center angle of the second connecting section 4 is 30° to 40°, and the corresponding center is located on the cooling secondary flow B side. The shape memory alloy temperature of the first connecting section 2 and the second connecting section 4 T s and dependent variable F The relationship is ;

[0025] In the formula ，M f 、M s 、A s and A f They represent the temperatures of the start of martensitic transformation, the end of martensitic transformation, the start of austenitic transformation and the end of austenitic transformation respectively; F max is the maximum deformation of shape memory alloy. T s < M f or M s < T s < A s hour, dF / dT s =0.

[0026] Furthermore, air film holes are provided on the front section 1, the first connecting section 2, the middle section 3, the second connecting section 4 and the rear section 5. Preferably, the inclination angle of the front section 1 is α The middle section 3 is horizontally set, and its inclination angle does not change with the memory alloy; the inclination angle of the rear section 5 β It is 20°~30°.

[0027] When the temperature of the cone surface of the center cone reaches the deformation temperature, the first connecting segment 2 and the second connecting segment 4 are deformed, and the inclination angles of the front segment 1 and the rear segment 5 change with the deformation of the first connecting segment 2 and the second connecting segment 4, and the cone size of the center cone changes accordingly, and the overall surface posture of the center cone in the afterburner is dynamically adjusted. The size of the air film holes on the front segment 1, the middle segment 3 and the rear segment 5 remains unchanged, while the size of the air film holes on the first connecting segment 2 and the second connecting segment 4 changes with the deformation of the first connecting segment 2 and the second connecting segment 4.

[0028] Furthermore, the air film holes are regularly arranged in the front section 1, the first connecting section 2, the middle section 3, the second connecting section 4 and the rear section 5, the aperture of the air film holes is greater than or equal to 1.0 mm and less than 1.5 mm, the air film hole row spacing is 10 mm, the air film hole pitch is 6 mm, the air film holes are all opened in the reverse direction of the mainstream direction, and the air film hole deflection angle design variable range of the front section 1, the middle section 3 and the rear section 5 is 15°~90°. Preferably, the air film hole deflection angle of the front section 1 is δ 1 is 55°, the deflection angle of the air film hole in the middle section 3 δ 2 is 45°, and the deflection angle of the air film hole in the rear section 5 is δ 3 is 30°. The shape of the air film hole is any one of a reference circular hole, a fan-shaped hole and a convergent slit hole. Among the three hole types, the fan-shaped hole has the best overall cooling effect, followed by the reference circular hole. Considering that the fan-shaped hole is a segmented expansion structure, it is difficult to process in actual combustion chamber applications, especially at a maximum aperture of 1-2 mm. Considering the cooling effect and the actual processing difficulty, the present invention preferably uses a reference circular hole.

[0029] The cone thickness is selected as 1.5mm, the diameter of the air film hole is selected as 1.0mm, the air film hole spacing (the distance between two air film holes along the flow direction) is selected as 10mm, and the air film hole pitch (the distance between two air film holes along the circumferential direction) is selected as 6mm. The air film hole opening rate (total area of ​​air film holes / surface area of ​​the cone surface of the central cone when no holes are opened) is set to 6.1%, the temperature of the high-temperature mainstream A is 1275 K, the pressure is 356kPa, the temperature of the cooling secondary flow B is 520K, the mass flow rate is 0.23kg / s, and the blowing ratio is defined as M for

[0030] ;

[0031] In the formula, m c , A c is the mass flow rate of cooling secondary flow B and the opening area of ​​the air film hole, m ∞ , A ∞ is the mass flow rate and the mainstream inlet area of ​​the high-temperature mainstream A. In this embodiment, the blowing ratio is selected M is 1.5.

[0032] In this embodiment, the central cone is a 1 / 4 rotation structure, and the rotation period boundary D is determined. After the cooling secondary flow B enters the calculation domain, it is ejected from the air film holes of the front section 1, the first connecting section 2, the middle section 3, the second connecting section 4 and the rear section 5 of the central cone, forming a cooling air film on the cone surface of the central cone to protect the wall surface and prevent the central cone from being corroded and damaged by high temperature. The cooling secondary flow B and the high-temperature mainstream A flow back, entrain, and mix above the cone, and then flow out from the channel outlet C, thereby realizing the functions of rectification and pressure expansion of the central cone structure.

[0033] In this embodiment, M f , M s , A s and A f They are 550K, 750K, 950K, and 1150K respectively. The flow field and temperature field are calculated by the commercial computing software Ansys CFX. The relative pressure loss of the main channel of the central cone Δ p * And the average spanwise comprehensive cooling efficiency of the center cone surface They are defined as

[0034] ;

[0035] In the formula, p * in is the total pressure at the inlet of the cooling secondary flow; p * out is the total pressure at the channel outlet.

[0036] ;

[0037] In the formula, T ∞ is the mainstream temperature, T w. s is the spanwise average wall temperature of the hot side of the central cone, T c is the cooling gas temperature, where the spanwise average wall temperature T w. s for

[0038] ;

[0039] In the formula, T w is the local wall temperature on the hot side of the central cone, s is the span direction of the center cone wall.

[0040] like Figure 4and Figure 5 As shown, x is the flow distance from the front end of the center cone, L is the length of the center cone, E is the rigid airless film hole connecting section of the center cone, at this time, the relative pressure loss of the center cone main channel is 0.35%, and the average span-wise comprehensive cooling efficiency of the center cone surface is 0.88; F is the center cone introducing the first connecting section 2 and the second connecting section 4 made of shape memory alloy with film holes to replace the rigid airless film hole connecting section, at this time, the relative pressure loss of the center cone main channel is 0.29%, and the average span-wise comprehensive cooling efficiency of the center cone surface is 0.93. The present invention reduces the relative pressure loss by 0.17%, that is, optimizes the aerodynamic performance of the film cooling structure of the center cone. The present invention increases the average span-wise comprehensive cooling efficiency by 5.7%, that is, optimizes the thermal performance of the film cooling structure of the center cone.

Claims

1. An aviation gas turbine engine, characterized in that: The invention comprises an afterburner, wherein the central cone of the afterburner is composed of a front section (1), a first connecting section (2), a middle section (3), a second connecting section (4) and a rear section (5) connected in sequence, wherein the front section (1), the middle section (3) and the rear section (5) are made of a high-temperature alloy, and the first connecting section (2) and the second connecting section (4) are made of a shape memory alloy. When the cone surface temperature of the central cone reaches the deformation temperature, the first connecting section (2) and the second connecting section (4) are deformed, and the inclination angle of the front section (1) and the inclination angle of the rear section (5) change with the deformation of the first connecting section (2) and the second connecting section (4), respectively, and the cone size of the central cone changes accordingly, and the overall surface posture of the central cone in the afterburner is dynamically adjusted; the front section (1), the middle section (3) and the rear section (5) are all provided with air film holes.

2. The aviation gas turbine engine according to claim 1, characterized in that: The first connecting section (2) and the second connecting section (4) are also provided with air film holes. When the first connecting section (2) and the second connecting section (4) are deformed, the air film holes on the first connecting section (2) and the second connecting section (4) change size accordingly.

3. The aviation gas turbine engine according to claim 1, characterized in that: The inclination angle of the front section (1) is 40° to 60°; the middle section (3) is arranged horizontally, and its inclination angle does not change with the memory alloy; and the inclination angle of the rear section (5) is 20° to 30°.

4. The aviation gas turbine engine according to claim 1, characterized in that: The shape memory alloy temperature of the first connecting section (2) and the second connecting section (4) T s and dependent variable F The relationship is ； In the formula ，M f 、M s 、A s and A f Respectively represent the temperatures of the start of martensitic transformation, the end of martensitic transformation, the start of austenitic transformation and the end of austenitic transformation; F max is the maximum deformation of shape memory alloy; when T s < M f or M s < T s < A s hour, dF / dT s =0.

5. The aviation gas turbine engine according to claim 1, characterized in that: The center angle of the first connecting section (2) is 35° to 60°, and the corresponding center is located on the high-temperature mainstream side; the center angle of the second connecting section (4) is 30° to 40°, and the corresponding center is located on the cooling secondary side.

6. The aviation gas turbine engine according to claim 2, characterized in that: The air film holes are regularly arranged on the front section (1), the first connecting section (2), the middle section (3), the second connecting section (4) and the rear section (5).

7. The aviation gas turbine engine according to claim 2, characterized in that: After the first connecting section (2) and the second connecting section (4) are deformed, the total opening area of ​​the air film holes on the first connecting section (2) and the second connecting section (4) increases by 0-10%.

8. The aviation gas turbine engine according to claim 2, characterized in that: The aperture of the air film holes is greater than or equal to 1.0 mm and less than 1.5 mm, the row spacing of the air film holes is 10 mm, the pitch of the air film holes is 6 mm, and the air film holes are all opened in the reverse direction of the high-temperature mainstream.

9. The aviation gas turbine engine according to any one of claims 2 to 8, characterized in that: The shape of the air film hole is a reference circular hole or a convergent slit hole.

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