Vortex generator, engine and aircraft

Abstract

The invention relates to a vortex generator, an engine and an aircraft, and relates to the technical field of aviation. The vortex generator comprises a base body, a mounting surface is arranged at the bottom of the base body, and the mounting surface is used for being mounted on the surface of a solid through which fluid passes; a windward side is arranged at the top of the base body, the windward side extends in the first direction, an inclined angle is formed between the windward side and the mounting surface, and the length of the windward side in the second direction is gradually reduced in the first direction, so that the base part is in a wedge shape; side faces are arranged on the two sides of the base body respectively, the side faces intersect with the mounting face and the windward face respectively, and the side faces are perpendicular to the mounting face; wherein the substrate is located within a boundary layer of the fluid. The technical scheme disclosed by the invention can effectively control shock wave / boundary layer interference.

Description

Technical Field

[0001] The present invention relates to the field of aviation technology, and in particular to a vortex generator, an engine and an aircraft. Background Art

[0002] Due to the speed and altitude characteristics of supersonic flight, a thick boundary layer forms on the vehicle's surface. Furthermore, due to the vehicle's geometrical shape, a series of shock waves are generated in the supersonic airflow. These shock waves are reflected from the vehicle's surface, and upon encountering the surface's boundary layer, shock wave / boundary layer interference occurs. Shock wave / boundary layer interference in the inlet flow field not only leads to thickening of the boundary layer and congestion within the inlet, but can also cause the inlet to fail to start, impacting engine operation. In some cases, vortex generators are used to control flow at the shock wave / boundary layer interference location, but existing vortex generators are unable to effectively control shock wave / boundary layer interference. Summary of the Invention

[0003] Embodiments of the present invention provide a vortex generator, an engine, and an aircraft, which can effectively control shock wave / boundary layer interference.

[0004] In a first aspect, an embodiment of the present invention provides a vortex generator, comprising a base, wherein a mounting surface is provided at the bottom of the base, and the mounting surface is used to be mounted on a solid surface through which a fluid passes; a windward surface is provided at the top of the base, and the windward surface extends along a first direction and has an inclination angle with the mounting surface, and the length of the windward surface in a second direction gradually decreases along the first direction so that the base is wedge-shaped; side surfaces are respectively provided on both sides of the base, and the side surfaces intersect with the mounting surface and the windward surface respectively, and the side surfaces are perpendicular to the mounting surface; wherein the base is located in the boundary layer of the fluid.

[0005] In one embodiment, the height of the vortex generator is H, and the thickness of the boundary layer is δ, wherein H and δ satisfy the following relationship: 0<H<δ.

[0006] In one embodiment, the windward surface is an isosceles triangle, and the side surface is a right triangle, wherein the mounting surface is an isosceles triangle, and the semi-vertex angle of the isosceles triangle is greater than 5° and less than 60°.

[0007] In one embodiment, the length of the isosceles side of the mounting surface is C, and the height of the vortex generator is H, wherein H and C satisfy the following relationship: H<C<50H.

[0008] In a second aspect, an embodiment of the present invention provides an engine comprising the vortex generator as described above.

[0009] In one embodiment, the engine includes a plurality of vortex generators, and the vortex generators are arranged at intervals along the second direction.

[0010] In one embodiment, there is a vortex spacing between two adjacent vortex generators, wherein the vortex spacing S, the half-apex angle Ap of the mounting surface, and the length C of the isosceles side of the mounting surface satisfy the following relationship: 2Csin(Ap)≤S≤10Csin(Ap).

[0011] In one embodiment, there is a streamwise distance between the vortex generator and the interference position of the boundary layer; wherein the streamwise distance L and the height H of the vortex generator satisfy the following relationship: 0≤L≤100H.

[0012] In a third aspect, an embodiment of the present invention provides an aircraft, comprising the engine as described above.

[0013] Compared with the prior art, the advantage of the embodiments of the present invention is that by arranging the base body in the boundary layer, the vortex generator plays a control role on the flow, and the bottom fluid of the boundary layer is sucked into the outer layer or even into the mainstream, thereby avoiding large-scale flow separation caused by the low flow velocity and kinetic energy of the bottom fluid of the boundary layer. By setting up an inclined windward surface and side surface with a gradually decreasing length in the second direction, the flow area of the fluid can be continuously expanded when flowing through the vortex generator, and the fluid expands laterally, while the fluid in the boundary layer is more susceptible to boundary changes, so that its lateral expansion is different from that of the mainstream, resulting in large lateral shear inside the boundary layer, and vortices are gradually generated in the side and installation surface corner areas; downstream of the vortex generator, the medium and low-speed flow in the boundary layer falls off at the tail of the vortex generator, shears with the mainstream, and forms a flow vortex; and there are vortices on both sides of the vortex generator, but in opposite directions, forming a counter-rotating vortex pair. As the rotating vortex pair develops downstream, it continuously sucks in the bottom fluid of the boundary layer, causing the low-energy flow in the bottom of the boundary layer to mix with the external mainstream, so that the kinetic energy of the fluid in the boundary layer is increased, thereby enhancing the resistance to the rapid pressurization caused by the shock wave and suppressing the large-area flow separation caused by the shock wave / boundary layer interference. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Hereinafter, the present invention will be described in more detail based on embodiments with reference to the accompanying drawings.

[0015] Figure 1 1 is a schematic structural diagram of a vortex generator provided by an embodiment of the present invention;

[0016] Figure 2 yes Figure 1 Schematic diagram of vortex generated downstream of vortex generator in the embodiment;

[0017] Figure 3is a schematic diagram of the effect of a vortex generator in oblique shock wave / boundary layer interference provided by another embodiment of the present invention;

[0018] Figure 4 It is a schematic diagram of the effect of a vortex generator provided by another embodiment of the present invention on the lip shroud shock wave / boundary layer interference of a high-speed inlet.

[0019] Reference numerals:

[0020] 1. Mounting surface; 2. Windward surface; 3. Side surface; 4. Rotating vortex pair; 5. Cross flow; 6. Shock generator; 7. Oblique shock wave; 8. Lower wall; 9. Inlet lip cover; 10. Lip cover shock wave; 11. Vortex generator. DETAILED DESCRIPTION

[0021] The present invention will be further described below with reference to the accompanying drawings.

[0022] Due to the speed and altitude characteristics of supersonic flight, a thick boundary layer forms on the vehicle's surface. Furthermore, due to the vehicle's geometrical shape, a series of shock waves are generated in the supersonic airflow. These shock waves are reflected from the vehicle's surface, and upon encountering the surface's boundary layer, shock wave / boundary layer interference occurs. Shock wave / boundary layer interference in the inlet flow field not only leads to thickening of the boundary layer and congestion within the inlet, but can also cause the inlet to fail to start, impacting engine operation. In some cases, vortex generators are used to control flow at the shock wave / boundary layer interference location, but existing vortex generators are unable to effectively control shock wave / boundary layer interference.

[0023] Example 1

[0024] like Figure 1 、 Figure 2 As shown, in order to solve the above technical problems, an embodiment of the present invention provides a vortex generator, including a base, a mounting surface 1 is provided at the bottom of the base, and the mounting surface 1 is used to be installed on a solid surface through which a fluid passes; a windward surface 2 is provided on the top of the base, and the windward surface 2 extends along a first direction and has an inclination angle with the mounting surface 1, and the length of the windward surface 2 in the second direction gradually decreases along the first direction, so that the base is wedge-shaped; side surfaces 3 are respectively provided on both sides of the base, and the side surfaces 3 intersect with the mounting surface 1 and the windward surface 2 respectively, and the side surfaces 3 are perpendicular to the mounting surface 1; wherein, the base is located in the boundary layer of the fluid.

[0025] As can be seen from the above, by setting the substrate in the boundary layer, the vortex generator can exert its control effect on the flow, and the bottom fluid of the boundary layer can be sucked into the outer layer or even the mainstream, avoiding large-scale flow separation caused by the low flow velocity and kinetic energy of the bottom fluid of the boundary layer. By setting an inclined windward surface 2 and a side surface 3 with a gradually decreasing length in the second direction, the flow area of the fluid can be continuously expanded when flowing through the vortex generator, and the fluid expands laterally, while the fluid in the boundary layer is more susceptible to boundary changes, so that its lateral expansion is different from that of the mainstream, resulting in large lateral shear inside the boundary layer, and vortices are gradually generated in the corner area of the side surface 3 and the mounting surface 1; downstream of the vortex generator, the medium and low-speed flow in the boundary layer falls off at the tail of the vortex generator, shears with the mainstream, and forms a flow vortex; and there are vortices on both sides 3 of the vortex generator, but in opposite directions, forming a counter-rotating vortex pair 4. As the rotating vortex pair 4 develops downstream, it continuously sucks in the bottom fluid of the boundary layer, causing the low-energy flow in the bottom of the boundary layer to mix with the external mainstream, so that the kinetic energy of the fluid in the boundary layer is increased, thereby enhancing the resistance to the rapid pressurization caused by the shock wave and suppressing the large-area flow separation caused by the shock wave / boundary layer interference.

[0026] It should be noted that if Figure 1 As shown, the first direction is parallel to the X direction, and the second direction is parallel to the Y direction.

[0027] It should also be noted that the solid surface that the fluid passes through is the location where the low momentum boundary layer is formed during the fluid flow, including but not limited to the aerodynamic surfaces of the fan wings, vertical tail, horizontal tail, or the inlet and outlet surfaces of the engine; in addition, Figure 2 As shown, the fluid flows along a first direction, an angle is formed between the shock wave surface and the flow direction of the fluid, and the shock wave hits the windward surface 2 .

[0028] It should also be noted that the inclination angle between the mounting surface 1 and the windward surface 2 is less than 90°.

[0029] Example 2

[0030] like Figure 1 、 Figure 2 As shown, the vortex generator includes a base, a mounting surface 1 is provided at the bottom of the base, and the mounting surface 1 is used to be mounted on a solid surface through which a fluid passes; a windward surface 2 is provided on the top of the base, the windward surface 2 extends along a first direction and has an inclination angle with the mounting surface 1, and the length of the windward surface 2 in a second direction gradually decreases along the first direction, so that the base is wedge-shaped; side surfaces 3 are respectively provided on both sides of the base, the side surfaces 3 intersect with the mounting surface 1 and the windward surface 2 respectively, and the side surfaces 3 are perpendicular to the mounting surface 1; wherein, the base is located in the boundary layer of the fluid.

[0031] As can be seen from the above, by setting the substrate in the boundary layer, the vortex generator can exert its control effect on the flow, and the bottom fluid of the boundary layer can be sucked into the outer layer or even the mainstream, avoiding large-scale flow separation caused by the low flow velocity and kinetic energy of the bottom fluid of the boundary layer. By setting an inclined windward surface 2 and a side surface 3 with a gradually decreasing length in the second direction, the flow area of the fluid can be continuously expanded when flowing through the vortex generator, and the fluid expands laterally, while the fluid in the boundary layer is more susceptible to boundary changes, so that its lateral expansion is different from that of the mainstream, resulting in large lateral shear inside the boundary layer, and vortices are gradually generated in the corner area of the side surface 3 and the mounting surface 1; downstream of the vortex generator, the medium and low-speed flow in the boundary layer falls off at the tail of the vortex generator, shears with the mainstream, and forms a flow vortex; and there are vortices on both sides 3 of the vortex generator, but in opposite directions, forming a counter-rotating vortex pair 4. As the rotating vortex pair 4 develops downstream, it continuously sucks in the bottom fluid of the boundary layer, causing the low-energy flow in the bottom of the boundary layer to mix with the external mainstream, so that the kinetic energy of the fluid in the boundary layer is increased, thereby enhancing the resistance to the rapid pressurization caused by the shock wave and suppressing the large-area flow separation caused by the shock wave / boundary layer interference.

[0032] It should be noted that if Figure 1 As shown, the first direction is parallel to the X direction, and the second direction is parallel to the Y direction.

[0033] It should also be noted that the solid surface that the fluid passes through is the location where the low momentum boundary layer is formed during the fluid flow, including but not limited to the aerodynamic surfaces of the fan wings, vertical tail, horizontal tail, or the inlet and outlet surfaces of the engine; in addition, Figure 2 As shown, the fluid flows along a first direction, an angle is formed between the shock wave surface and the flow direction of the fluid, and the shock wave hits the windward surface 2 .

[0034] It should also be noted that the inclination angle between the mounting surface 1 and the windward surface 2 is less than 90°.

[0035] In some embodiments, the height of the vortex generator is H, and the thickness of the boundary layer is δ, wherein H and δ satisfy the following relationship: 0<H<δ.

[0036] By limiting the height of the vortex generator to be smaller than the thickness of the boundary layer, the vortex generator is ensured to be completely located in the boundary layer, and the size of the vortex generator is reduced, thereby reducing the additional resistance caused by the vortex generator in the boundary layer.

[0037] like Figure 1 As shown, in some embodiments, the windward surface 2 is an isosceles triangle and the side surface 3 is a right triangle; wherein, the mounting surface 1 is an isosceles triangle, and the semi-vertex angle of the isosceles triangle is greater than 5° and less than 60°.

[0038] Because the vortex generator is wider in the first direction and narrower in the back, the blockage it causes to the fluid gradually decreases, thereby increasing the flow area. By limiting the half-apex angle of the mounting surface 1, the expansion rate of the fluid flow area can be controlled, thereby controlling the development of the vortex and the mixing between the low-energy flow in the boundary layer, the outer layer of the boundary layer, and the main flow, thereby adjusting the vortex generator's control effect on the fluid in the boundary layer.

[0039] It should be noted that if Figure 1 As shown, the half apex angle of the mounting surface 1 is Ap, ie, half of the apex angle of the mounting surface 1 .

[0040] like Figure 1 As shown, in some embodiments, the length of the isosceles side of the mounting surface 1 is C, and the height of the vortex generator is H, wherein H and C satisfy the following relationship: H<C<50H.

[0041] By limiting the length of the isosceles side of mounting surface 1, the expansion rate of the fluid flow area can be controlled, thereby controlling the development of vortices and the mixing between the rotating vortex pairs 4 of the low-energy flow in the boundary layer and the outer layer of the boundary layer and the mainstream, thereby adjusting the control effect of the vortex generator on the fluid in the boundary layer. On the one hand, it is necessary to avoid the isosceles side length C of mounting surface 1 being too small. When C is less than H, the vortex generator will resemble a cylindrical structure, resulting in poor control effect on the fluid in the boundary layer. On the other hand, it is also necessary to avoid the isosceles side length C of mounting surface 1 being too large. When C is greater than 50H, the vortex generator will be too long, resulting in the vortex generator resembling a small slope structure, resulting in poor control effect on the fluid in the boundary layer.

[0042] Example 3

[0043] An embodiment of the present invention further provides an engine, comprising the vortex generator 11 described in any embodiment of the present invention, thereby having all the technical effects brought about by the technical solutions of the above embodiments.

[0044] It should be noted that the engine includes an air intake duct, a combustion chamber and a tail pipe section. The air intake duct is the air intake device of the engine, which can capture air with a flow rate that meets the propulsion requirements, decelerate and boost it, and provide air with a certain pressure, temperature and speed for organizing combustion in the combustion chamber; among them, the vortex generator 11 is arranged on the lower wall 8 of the air intake duct.

[0045] like Figure 2 As shown, in some embodiments, the engine includes a plurality of vortex generators 11 , and the vortex generators 11 are arranged at intervals along the second direction.

[0046] like Figure 1-Figure 3As shown, in some embodiments, there is a vortex spacing between two adjacent vortex generators 11, wherein the vortex spacing S, the half-vertex angle Ap of the mounting surface 1, and the length C of the isosceles side of the mounting surface 1 satisfy the following relationship: 2Csin(Ap)≤S≤10Csin(Ap).

[0047] By adjusting the spacing between vortex generators 11, their control effect on the crossflow 5 field can be adjusted. By limiting the size of the vortex spacing S, the control effect on the fluid in the boundary layer is guaranteed. On the one hand, it is important to avoid a vortex spacing S that is too small. When S is less than 2Csin(Ap), the vortices generated between two vortex generators arranged side by side will interfere with each other, affecting the control effect on the flow. On the other hand, it is also important to avoid a vortex spacing S that is too large. When S is greater than 10Csin(Ap), the vortices generated are too sparse in space, which also reduces the control effect.

[0048] It should be noted that the oblique shock wave / boundary layer interference is caused by the oblique shock wave 7 bringing an adverse pressure gradient to the boundary layer, and the oblique shock wave 7 is generated by the sudden turn of the supersonic airflow when encountering an object. Therefore, the oblique shock wave 7 will also be generated when encountering an inward corner on the wall of the inlet; Figure 3 As shown, the shock wave generator 6 generates an oblique shock wave 7 which interacts with the boundary layer developed on the lower wall surface 8 of the inlet duct. By arranging the vortex generator 11 on the lower wall surface 8, the rotating vortex pair 4 generated by the vortex generator 11 can be effectively utilized to enhance the mixing of the boundary layer and the mainstream, thereby increasing the kinetic energy of the fluid in the boundary layer, enhancing the resistance to the rapid pressurization caused by the shock wave, and then suppressing the flow separation, thereby controlling the shock wave / boundary layer interference; in addition, for the flow in a limited lateral space, an array of vortex generators 11 can be used, and the control effect on the oblique shock wave / boundary layer can be further improved by the vortex spacing S and the flow spacing L.

[0049] It should also be noted that the specific value of the flow spacing L can be adjusted according to the incoming flow conditions and the intensity of the oblique shock wave 7 .

[0050] like Figure 1-Figure 3 As shown, in some embodiments, there is a streamwise spacing between the vortex generator 11 and the interference position of the boundary layer; wherein the streamwise spacing L and the height H of the vortex generator 11 satisfy the following relationship: 0≤L≤100H.

[0051] By controlling the size of the flow spacing, the development of the boundary layer can be controlled, thereby having a favorable effect on the shock wave / boundary layer interference and avoiding the flow spacing L being too large. When L is greater than 100H, the vortex generator will be similar to a slope structure with a small slope, which has poor control effect on the fluid in the boundary layer, and the compression caused by the slope structure will have an adverse effect.

[0052] It should be noted that the lip shock wave 10 is a shock wave formed near the inlet lip 9, which is a special application form of the oblique shock wave 7. Specifically, in the inlet flow field, the fluid is compressed by the aircraft front body and enters the compression channel in the inlet at a certain angle to the aircraft body. It is compressed by the inlet lip to generate a strong lip shock wave. Figure 4 As shown, the fluid flows through the inlet lip mask 9, generating a lip mask shock wave 10. The lip mask shock wave 10 interacts with the boundary layer developed on the lower wall surface 8 of the inlet. By arranging a vortex generator 11 on the lower wall surface 8, the lip mask shock wave / boundary layer interference can be effectively controlled to improve the inlet performance. In addition, based on the basic flow field of the inlet and the intensity of the lip mask shock wave 10, the flow spacing can be adjusted to further improve the control effect of the lip mask shock wave / boundary layer and improve the aerodynamic performance of the inlet.

[0053] It should also be noted that the interference position of the boundary layer refers to the position where the shock wave hits the lower wall 8.

[0054] In addition, the specific values of the height H, half-apex angle Ap and other parameters of the vortex generator of the present invention need to be set in combination with the specific shock wave / boundary layer interference characteristics, which will be explained below in combination with the specific shock wave / boundary layer interference characteristics;

[0055] When the incoming flow Mach number is 2.9 and the unit Reynolds number is 5.6×10 5 m -1 The angle of the shock generator is 12°, the shock angle of the oblique shock wave is 30°, and the boundary layer thickness in front of the vortex generator is 6.7 mm. At this time, the oblique shock wave interacts with the boundary layer on the lower wall, resulting in local flow separation. The separation bubble height is about 1.2 mm. The size range of the vortex generator that can effectively control the separation is:

[0056] Height: 0.3δ≤H≤0.5δ

[0057] String length: 12H <C<20H

[0058] Half apex angle: 5° <Ap<12°

[0059] Micro eddy current generator spacing: 2Csin(Ap)≤S≤4Csin(Ap)

[0060] Flow distance L: 0≤L≤20H.

[0061] Example 4

[0062] An embodiment of the present invention provides an aircraft, comprising the engine described in any embodiment of the present invention, and thus having all the technical effects brought about by the technical solutions of the above embodiments.

[0063] While the present invention has been described with reference to preferred embodiments, various modifications may be made and equivalent components may be substituted without departing from the scope of the present invention. In particular, the various technical features described in the various embodiments may be combined in any manner, provided no structural conflicts exist. The present invention is not limited to the specific embodiments disclosed herein, but encompasses all technical solutions within the scope of the claims.

Claims

1. A vortex generator, characterized in that: The invention comprises a base, wherein a mounting surface is provided at the bottom of the base, and the mounting surface is used to be mounted on a solid surface through which a fluid passes; a windward surface is provided at the top of the base, and the windward surface extends along a first direction and has an inclination angle with the mounting surface, and the length of the windward surface in a second direction gradually decreases along the first direction so that the base is wedge-shaped; side surfaces are respectively provided on both sides of the base, and the side surfaces intersect with the mounting surface and the windward surface respectively, and the side surfaces are perpendicular to the mounting surface; wherein the base is located in the boundary layer of the fluid.

2. The vortex generator according to claim 1, characterized in that The height of the vortex generator is H, and the thickness of the boundary layer is δ, wherein H and δ satisfy the following relationship: 0<H<δ.

3. The vortex generator according to claim 1, characterized in that The windward surface is an isosceles triangle, and the side surface is a right-angled triangle, wherein the mounting surface is an isosceles triangle, and a semi-vertex angle of the isosceles triangle is greater than 5° and less than 60°.

4. The vortex generator according to claim 3, characterized in that The length of the isosceles side of the mounting surface is C, and the height of the vortex generator is H, wherein H and C satisfy the following relationship: H<C<50H.

5. An engine, characterized in that: The invention comprises a vortex generator according to any one of claims 1 to 4.

6. The engine according to claim 5, characterized in that The engine includes a plurality of vortex generators, and the vortex generators are arranged at intervals along the second direction.

7. The engine according to claim 6, characterized in that There is a vortex spacing between two adjacent vortex generators, wherein the vortex spacing S, the half-apex angle Ap of the mounting surface, and the length C of the isosceles side of the mounting surface satisfy the following relationship: 2Csin(Ap)≤S≤10Csin(Ap).

8. The engine according to claim 5, characterized in that There is a streamwise distance between the vortex generator and the interference position of the boundary layer; wherein the streamwise distance L and the height H of the vortex generator satisfy the following relationship: 0≤L≤100H.

9. An aircraft, characterized in that: Comprising an engine as claimed in any one of claims 5-8.

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