A design method for the two-dimensional aerodynamic surface of an aeroengine thrust reverser exhaust volute

Abstract

The present invention relates to a method for designing a two-dimensional aerodynamic surface of a reverse thrust exhaust volute for an aircraft engine, which belongs to the field of aircraft design technology and solves the problem in the prior art that the aerodynamic surface of the exhaust volute is complex in structure and difficult to process and assemble. The present invention provides a method for designing a two-dimensional aerodynamic surface of a reverse thrust exhaust volute for an aircraft engine, and according to the size of the engine exhaust port and the exhaust direction, the pressure surface, the first guide vane, the second guide vane and the suction surface are designed in sequence, wherein the pressure surface and the suction surface adopt an arc design with an extended line, and the guide vane adopts an arc design. The aerodynamic surface designed by the design method has a simple structure, significantly reduces the difficulty and cost of processing, and is convenient to assemble; the flow field in the reverse thrust exhaust volute using the above-mentioned aerodynamic surface is stable and unobstructed, the streamline / exhaust airflow leaving the volute outlet can smoothly enter the ejector tube, and the impact on the reverse thrust exhaust back pressure is ≤200Pa, and the exhaust effect is stable and excellent.

Description

Technical Field

[0001] The present invention relates to the technical field of aircraft design, and in particular to a design method for a two-dimensional aerodynamic surface of an aircraft engine reverse thrust exhaust volute. Background Art

[0002] During reverse thrust testing on an indoor test bench, the reverse thrust exhaust flow exits in the opposite direction of the engine's main thrust direction. Therefore, the reverse thrust exhaust may be re-inhaled by the engine during the reverse thrust test, causing intake conditions such as engine intake temperature and intake uniformity to deviate from the test operating conditions. In severe cases, this can lead to unstable engine operating conditions, resulting in damage or even danger. Therefore, re-inhalation of the reverse thrust exhaust flow should be avoided during reverse thrust testing.

[0003] During engine reverse thrust testing, a thrust reverser exhaust volute collects the airflow exhausted from the engine's thrust reverser blades and directs it to the rear of the engine and toward the ejector tube on the test bench, preventing it from being re-inhaled by the engine. Existing thrust reverser exhaust volutes often employ complex structural designs to achieve good exhaust performance. While these designs achieve good exhaust performance, their complex structures make machining difficult and costly, and assembly is challenging, requiring high operator skill. Summary of the Invention

[0004] In view of the above analysis, an embodiment of the present invention aims to provide a design method for the two-dimensional aerodynamic surface of an aircraft engine reverse thrust exhaust volute, so as to solve at least one of the problems in the prior art such as the complex structure of the aerodynamic surface of the exhaust volute, difficulty in processing (difficult processing and high cost) and assembly.

[0005] The present invention provides a method for designing a two-dimensional aerodynamic surface of an aircraft engine thrust reverser exhaust volute, wherein the aerodynamic surface comprises, from left to right, a pressure surface, a first guide vane, a second guide vane, and a suction surface, wherein the pressure surface and the suction surface are arcs with extension lines at the exhaust end, and the first guide vane and the second guide vane are arcs;

[0006] The specific steps include:

[0007] S1: According to the axial length L of the engine exhaust port x Determine the arc radius R of the pressure surface 压力面 , and according to the engine exhaust angle θ 发动机 , that is, the volute intake angle θ 进气 , determine the arc tangent angle of the air inlet end of the pressure surface;

[0008] S2: Determine the exhaust angle θ of the volute according to the position of the ejector tube 排气, determine the arc tangent angle of the outlet end of the pressure surface according to the exhaust angle, that is, the extension line angle;

[0009] S3: Determine the arc radius R of the suction surface according to the arc radius of the pressure surface 吸力面 The tangent angles of the air inlet and air outlet ends of the suction surface arc are the same as the tangent angles of the corresponding ends of the pressure surface arc;

[0010] S4: Determine the installation positions of the pressure surface and the suction surface intake ends according to the size of the engine exhaust port; determine the virtual intake end positions of the first guide vane and the second guide vane according to the size of the engine exhaust port, and the closest intersection point of the complete circle corresponding to the guide vane arc and the plane where the engine exhaust port is located is the virtual intake end;

[0011] S5: the tangent angles of the virtual air inlet and air outlet ends of the arcs of the first guide vane and the second guide vane are the same as the tangent angles of the corresponding ends of the arc of the pressure surface;

[0012] S6: Draw a line connecting the center of the circle corresponding to the pressure surface arc and the center of the circle corresponding to the suction surface arc, and draw perpendicular lines to the tangents of the volute intake angle from the virtual intake ends of the first guide vane and the second guide vane, respectively. The intersection of the perpendicular lines and the connecting lines is the center position of the circle corresponding to the arc of the first guide vane and the second guide vane, thereby determining the radius of the first guide vane and the second guide vane;

[0013] S7: removing a portion of each of the first guide vane and the second guide vane from the virtual air inlet end to obtain an actual air inlet end, that is, to obtain a final aerodynamic profile;

[0014] Among them, the engine exhaust angle θ 发动机 and θ 进气 is the angle with the vertical direction, the volute exhaust angle θ 排气 It is the angle with the horizontal direction, with the counterclockwise direction as positive and the clockwise direction as negative; the left and right direction is the axial direction X, and the direction perpendicular to the paper is the circumferential direction Y.

[0015] Specifically, the arc extension line of the suction surface is ≥150mm;

[0016] After determining the end point of the suction surface arc extension line, draw a perpendicular line from this point to the suction surface arc extension line. The intersection of the perpendicular line and the pressure surface arc extension line is the end point of the pressure surface arc extension line.

[0017] Specifically, for any point of the engine exhaust port, the centers of the arcs corresponding to the pressure surface, the first guide vane, the second guide vane, and the suction surface are located on the same side of the vertical line and the four points are collinear; the four centers of the circles and the engine exhaust direction are located on opposite sides of the vertical line.

[0018] Specifically, in step S1, R压力面 The method of determining is to take twice the axial length L of the engine exhaust port x The distance upward or downward shall be rounded to the nearest integer multiple of 100 mm;

[0019] 2L x When the value is an integer multiple of 100mm, both the closest value upward and the closest value downward meet the design requirements, and there is no need to compare the closest value upward and the closest value downward with 2L. x The size of the difference between .

[0020] Specifically, θ 发动机 is 30°~50°, θ 排气 It is -10°~-20°.

[0021] Specifically, in step S3, R 吸力面 The method to determine R is: 吸力面 =R 压力面 -3*(100~150).

[0022] Specifically, the installation position of the pressure surface air inlet end is located 110 to 130 mm outside the left edge of the engine exhaust port, and the installation position of the suction surface air inlet end is located outside the right edge of the engine exhaust port, and is symmetrical to the installation position of the pressure surface air inlet end; the virtual air inlet end position of the first guide vane overlaps with the left edge of the engine exhaust port; the virtual air inlet end position of the second guide vane overlaps with the right edge of the engine exhaust port.

[0023] Specifically, in step S7, the removal length of the first guide plate or the second guide plate is 80-100 mm, and the removal lengths of the two are the same.

[0024] The present invention also provides a three-dimensional aerodynamic surface, which is obtained by circumferentially expanding the two-dimensional aerodynamic surface designed by the design method; the circumferential lengths of the pressure surface, the first guide vane, the second guide vane and the suction surface are the same and not less than the circumferential length L of the engine exhaust port. Y .

[0025] The present invention also provides an aero-engine thrust reverse exhaust volute, the exhaust volute comprising the three-dimensional aerodynamic surface;

[0026] The exhaust volute further comprises two front and rear restraint surfaces, the aerodynamic profile is fixed in the middle of the restraint surfaces, and the aerodynamic profile and the restraint surfaces together constitute a box-type aircraft engine reverse thrust exhaust volute.

[0027] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0028] 1. The two-dimensional aerodynamic surface designed by the present invention greatly simplifies the structure while ensuring the exhaust effect, significantly reduces the difficulty of processing and assembly, and reduces the processing cost and operator level requirements.

[0029] When designing the two-dimensional aerodynamic profile of the reverse thrust exhaust volute, the present invention uses a straight line plus an arc as the suction surface and the pressure surface of the aerodynamic profile. The aerodynamic scheme adopts a double-guide vane volute scheme, and the shapes of the suction surface and the pressure surface of the volute and the shape of the guide vanes are determined according to the axial length of the engine exhaust outlet (or nacelle outlet), the reverse thrust exhaust airflow angle and the volute exhaust angle. The above-mentioned aerodynamic profile can significantly improve the gas flow state in the volute.

[0030] 2. The two-dimensional aerodynamic surface design of the thrust-reversing exhaust volute designed in the present invention can produce a volute product suitable for the exhaust ports of various engines by constructing a three-dimensional aerodynamic surface axially symmetrically within the required circumferential range.

[0031] 3. The aerodynamic profile of the reverse thrust exhaust volute designed in the present invention makes the flow field inside the volute stable and unobstructed, the streamline / exhaust airflow leaving the volute outlet can smoothly enter the ejector tube, and the impact on the reverse thrust exhaust back pressure is ≤200Pa, the gas leakage is low (almost no leakage), and the exhaust effect is stable and excellent.

[0032] In the present invention, the above-mentioned technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of the present invention will be described in the following description, and some advantages will become apparent from the description or be learned through practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the contents particularly pointed out in the description and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like parts throughout the drawings.

[0034] Figure 1 Schematic diagram of the two-dimensional aerodynamic surface structure in Example 1;

[0035] Figure 2 Schematic diagram of the volute streamlines in Example 1 (simulation);

[0036] Figure 3 Schematic diagram of volute forward leakage in Example 1 (simulation);

[0037] Figure 4 Schematic diagram of backward leakage of the volute in Example 1 (simulation);

[0038] Figure 5 Schematic diagram of the three-dimensional structure of the volute in Example 1.

[0039] Reference numerals:

[0040] 1. Pressure surface; 2. First guide vane; 3. Second guide vane; 4. Suction surface; 5. Constraint surface. DETAILED DESCRIPTION

[0041] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, and are not used to limit the scope of the present invention.

[0042] In existing technologies, the commonly adopted solution is to prioritize the aerodynamic performance requirements of the reverse thrust exhaust volute when designing it, without optimizing the complex aerodynamic profile; or to prioritize a reverse thrust exhaust volute structure that is easy to process or assemble, and then design the aerodynamic profile based on this. Traditional solutions prioritize and determine one of the two: aerodynamic performance or processing and manufacturing, then require the other to cooperate during the design process, which brings difficulties to implementation and fails to properly balance these two aspects. Furthermore, the existing technology does not provide a detailed design scheme for the reverse thrust exhaust volute guide vane.

[0043] After extensive literature research and summary, this paper proposes that when designing the thrust reverser exhaust volute, the following must be met: 1. The thrust reverser exhaust must not be re-inhaled by the engine; 2. The thrust reverser exhaust volute has a minimal impact on the back pressure at the thrust reverser exhaust outlet; 3. The leakage between the thrust reverser exhaust volute and the nacelle must be minimal. On this basis, the difficulty of machining and assembling the volute should be taken into consideration to further reduce costs and the required operator skills.

[0044] The present invention provides a method for designing a two-dimensional aerodynamic surface of an aircraft engine thrust reverser exhaust volute, wherein the aerodynamic surface comprises, from left to right, a pressure surface, a first guide vane, a second guide vane, and a suction surface, wherein the pressure surface and the suction surface are arcs with extension lines at the exhaust end, and the first guide vane and the second guide vane are arcs;

[0045] Verified by simulation, the above structural design has excellent exhaust effect while significantly reducing the processing difficulty.

[0046] The design method specifically comprises the following steps:

[0047] S1: According to the axial length L of the engine exhaust port x Determine the arc radius R of the pressure surface 压力面 , and according to the engine exhaust angle θ 发动机 , that is, the volute intake angle θ 进气 , determine the arc tangent angle of the pressure surface inlet end, that is, the arc tangent angle of the pressure surface inlet end = θ 进气The tangent angle of the arc at the air inlet end of the volute is the same as the air inlet angle of the volute, which is conducive to the better transition of the reverse exhaust from the initial exhaust direction to the rear exhaust, avoiding the additional pressure loss caused by the component velocity perpendicular to the volute wall when the reverse exhaust enters the volute.

[0048] S2: Determine the exhaust angle θ of the volute according to the position of the ejector tube 排气 , determine the arc tangent angle of the outlet end of the pressure surface according to the exhaust angle, that is, the extension line angle;

[0049] S3: Determine the arc radius R of the suction surface according to the arc radius of the pressure surface 吸力面 The tangent angles of the air inlet and air outlet ends of the suction surface arc are the same as the tangent angles of the corresponding ends of the pressure surface arc;

[0050] S4: Determine the installation positions of the pressure surface and the suction surface intake ends according to the size of the engine exhaust port; determine the virtual intake end positions of the first guide vane and the second guide vane according to the size of the engine exhaust port, and the closest intersection point of the complete circle corresponding to the guide vane arc and the plane where the engine exhaust port is located is the virtual intake end;

[0051] S5: the tangent angles of the virtual air inlet and air outlet ends of the arcs of the first guide vane and the second guide vane are the same as the tangent angles of the corresponding ends of the arc of the pressure surface;

[0052] S6: Draw a line connecting the center of the circle corresponding to the pressure surface arc and the center of the circle corresponding to the suction surface arc, and draw perpendicular lines to the tangents of the volute intake angle from the virtual intake ends of the first guide vane and the second guide vane, respectively. The intersection of the perpendicular lines and the connecting lines is the center position of the circle corresponding to the arc of the first guide vane and the second guide vane, thereby determining the radius of the first guide vane and the second guide vane;

[0053] S7: removing a portion of each of the first guide vane and the second guide vane from the virtual air inlet end to obtain an actual air inlet end, that is, to obtain a final aerodynamic profile;

[0054] Among them, the engine exhaust angle θ 发动机 and θ 进气 is the angle with the vertical direction, the volute exhaust angle θ 排气 It is the angle with the horizontal direction, with the counterclockwise direction as positive and the clockwise direction as negative; the left and right direction is the axial direction X, and the direction perpendicular to the paper is the circumferential direction Y.

[0055] Specifically, the arc extension line of the suction surface is ≥150mm. The volute outlet length can be appropriately shortened according to the volute weight requirement, but it should not be too short and should at least exceed the outlet end point of the suction surface arc by 150mm.

[0056] After determining the end point of the suction surface arc extension line, draw a perpendicular line from this point to the suction surface arc extension line. The intersection of the perpendicular line and the pressure surface arc extension line is the end point of the pressure surface arc extension line.

[0057] Specifically, at any point on the engine exhaust port, the centers of the arcs corresponding to the pressure surface, first guide vane, second guide vane, and suction surface are located on the same side of a vertical line and are collinear. These four centers are located on opposite sides of the vertical line from the engine exhaust direction. In layman's terms, when the engine exhaust port is directed upward and to the left, each arc on the aerodynamic profile curves to the right.

[0058] Specifically, in step S1, R 压力面 The method of determining is to take twice the axial length L of the engine exhaust port x And take the nearest integer multiple of 100mm upward or downward to facilitate subsequent processing; x When the value is an integer multiple of 100mm, both the closest value upward and the closest value downward meet the design requirements, and there is no need to compare the closest value upward and the closest value downward with 2L. x The size of the difference between .

[0059] It's worth noting that the pressure surface primarily directs the engine's reverse thrust exhaust from the front of the engine to the rear. A larger pressure surface radius results in a smoother transition in the reverse thrust exhaust direction and lower reverse thrust exhaust pressure drop. However, an excessively large pressure surface radius can cause the reverse thrust exhaust volute to clash with structures like the engine mounts. This also increases the size of the volute mounts, creating another conflict with the engine mounts and other structures, rendering the volute unusable in practice. Therefore, the radius of the reverse thrust exhaust volute's pressure surface must be strictly controlled.

[0060] Specifically, θ 发动机 is 30°~50°, θ 排气 After the reverse thrust exhaust is guided by the volute, the direction is deflected from the front of the engine to the rear of the engine and enters the ejector tube. In order to ensure that the reverse thrust exhaust can enter the ejector tube smoothly, θ 排气 It should be a negative value to make the reverse thrust exhaust deflect toward the engine axis; but θ 排气 Too large will cause the reverse thrust exhaust and the internal exhaust of the engine to interfere with each other, which may cause the reverse thrust exhaust and the internal high-temperature exhaust to not fully enter the ejector tube, causing damage to the engine and other equipment in the test room. 排气 Should be a finite negative value.

[0061] Specifically, in step S3, R 吸力面 The method to determine R is: 吸力面 =R 压力面-3*(100~150). When determining the radius of the suction surface arc, we must first ensure that the arc of the suction surface cannot intersect with the arc of the pressure surface, otherwise the volute cannot be used. Therefore, it is necessary to subtract a part of the pressure surface radius to obtain the suction surface radius; at the same time, the suction surface radius cannot be too small. In order to allow the reverse thrust exhaust to enter the ejector smoothly, a contraction section is usually made at the outlet end of the volute to reduce the flow area and increase the exhaust flow rate. If a contraction section cannot be made, the volute outlet area must be kept as small as possible as much as possible. The inlet area here refers to the inlet enclosed by the two internal guide vanes, because the reverse thrust exhaust mainly flows between these two guide vanes. After a large number of experimental tests, optimization and summary, the pressure surface radius minus an integer multiple of 100 to 150 mm is the suction surface radius, where the integer multiple is the number of guide vanes + 1.

[0062] Furthermore, if the axial length of the nacelle outlet (or exhaust port; in actual production, the nacelle outlet and exhaust port are directly connected and have similar structural dimensions, and are considered to be substantially equivalent in this invention) does not exceed 400mm, then an integer multiple of 100mm is selected. If it exceeds 600mm, then an integer multiple of 150mm is selected. If the nacelle outlet axial length is between 400 and 600mm, then an appropriate value between 100 and 150mm can be selected. In Example 1, the nacelle outlet length is 550mm. Considering practical manufacturing and considering that this length is closer to 600mm, 150mm was used for calculation and design during the design process.

[0063] Specifically, the installation position of the pressure surface air inlet end is located 110 to 130 mm outside the left edge of the engine exhaust port, and the installation position of the suction surface air inlet end is located outside the right edge of the engine exhaust port, and is symmetrical to the installation position of the pressure surface air inlet end; the virtual air inlet end position of the first guide vane overlaps with the left edge of the engine exhaust port; the virtual air inlet end position of the second guide vane overlaps with the right edge of the engine exhaust port.

[0064] It is worth noting that in order to ensure that the reverse thrust exhaust can smoothly enter the volute, the axial length of the volute needs to exceed the axial length of the reverse thrust exhaust outlet (or engine nacelle outlet), which will make it difficult for the suction surface and pressure surface of the reverse thrust exhaust volute to simultaneously guide the reverse thrust exhaust entering the volute so that it can be smoothly deflected from the initial direction to the volute exhaust direction, thereby increasing the total pressure loss of the reverse thrust exhaust airflow in the volute and increasing the reverse thrust exhaust back pressure. In response to this situation, the present invention guides the reverse thrust exhaust by arranging guide vanes at specific positions in the volute, thereby reducing the total pressure loss of the reverse thrust exhaust in the volute and avoiding a significant impact on the reverse thrust exhaust back pressure. At the same time, since the distance between the pressure surface and the suction surface is slightly larger than the axial length L of the reverse thrust exhaust outlet, x This can avoid air leakage (such as Figure 3 、 Figure 4 shown).

[0065] Specifically, in step S7, the length of the first guide vane or the second guide vane removed is 80 to 100 mm, and the lengths removed for both are the same. The above design is to reduce the total pressure loss caused by the guide vane and avoid a significant impact on the reverse thrust exhaust back pressure.

[0066] Furthermore, the two-dimensional aerodynamic profile of the thrust reverser exhaust volute is determined according to the above method, and a three-dimensional aerodynamic profile can be constructed axisymmetrically based on the circumferential range of the thrust reverser exhaust outlet, and the circumferential shape of the three-dimensional volute inlet can be adjusted based on the circumferential shape of the engine.

[0067] The present invention also provides a three-dimensional aerodynamic surface, which is obtained by circumferentially expanding the two-dimensional aerodynamic surface designed by the design method; the circumferential lengths of the pressure surface, the first guide vane, the second guide vane and the suction surface are the same and not less than the circumferential length L of the engine exhaust port. Y .

[0068] The present invention also provides an aero-engine thrust reverse exhaust volute, the exhaust volute comprising the three-dimensional aerodynamic surface;

[0069] The exhaust volute further comprises two front and rear restraint surfaces, the aerodynamic profile is fixed in the middle of the restraint surfaces, and the aerodynamic profile and the restraint surfaces together constitute a box-type aircraft engine reverse thrust exhaust volute.

[0070] Specifically, the three-dimensional pneumatic profile can be fixed on the restraining surface by bonding, splicing or welding.

[0071] Example 1

[0072] 1. The axial length of the engine nacelle outlet (exhaust port) is 550mm. The arc radius of the volute pressure surface is determined to be twice this length (1100mm). For ease of processing, the arc radius is appropriately set upward or downward to an integer multiple of 100mm, which is 1100mm in this case. Then, based on the reverse thrust exhaust airflow angle (vertical angle), the volute inlet angle is determined to be 40°. To ensure that the reverse thrust exhaust can smoothly enter the ejector tube after passing through the volute, the volute exhaust angle and the horizontal angle are determined to be -15°, resulting in an airflow deflection angle of 145°. The arc shape of the volute pressure surface is determined based on the arc radius of 1100mm, the volute inlet angle of 40°, the volute exhaust angle of -15°, and the airflow deflection angle of 145°.

[0073] 2. The radius of the volute suction side arc is smaller than the radius of the pressure side arc. In this case, the number of guide vanes in the volute is two. Dividing the space inside the volute into three parts, subtract 3 × 150 mm from the pressure side arc radius to obtain the suction side arc radius (1100 mm - 3 × 150 mm = 650 mm). The shape of the volute suction side arc is determined based on the arc radius of 650 mm, the volute inlet angle of 40°, the volute exhaust angle of -15°, and the airflow deflection angle of 145°.

[0074] 3. Draw tangent lines at the endpoints of the arcs on the pressure and suction sides of the volute and extend them to obtain the profile of the volute outlet. The volute outlet length can be shortened appropriately based on the volute weight requirements, but it should not be too short and should extend at least 150mm beyond the endpoint of the arc on the suction side. In this case, the volute outlet extends approximately 350mm beyond the endpoint of the suction side.

[0075] 4. Before determining the position of the guide vanes, first determine the positional relationship between the volute and the engine. The clearance between the volute and the engine is 120mm, and the distance between the end point of the volute pressure surface and the leading edge of the engine nacelle outlet is the same as the distance between the end point of the volute suction surface and the trailing edge of the engine nacelle outlet.

[0076] 5. The inlet and outlet angles of the guide vane (virtual intake end) are identical to the volute inlet angles of 40° and the outlet angle of -15°, and the airflow deflection angles are also identical. To reduce the total pressure loss caused by the guide vane and avoid a significant impact on the reverse thrust exhaust backpressure, the guide vane at the volute inlet is partially removed, with both guide vanes being removed by approximately 90mm.

[0077] 6. Based on the above scheme, the two-dimensional aerodynamic surface of the reverse thrust exhaust volute is determined. The three-dimensional aerodynamic surface can be constructed axially symmetrically based on the circumferential range of the reverse thrust exhaust outlet. The circumferential shape of the three-dimensional volute inlet is adjusted according to the circumferential shape of the engine. (During the simulation, only the two-dimensional surface simulation is performed, so the circumferential length L of the engine nacelle outlet (exhaust port) is not calculated here. Y In fact, the circumferential length has little effect on the gas flow pattern and can be basically ignored.)

[0078] The above-mentioned profiles were simulated for exhaust conditions, and the fluid simulation software Fluent was used to test the engine in the reverse thrust design point state and the slow running state. The reverse thrust exhaust cascade, the internal nozzle, and the test chamber inlet were set with pressure inlet boundary conditions, the ejector outlet was set with pressure outlet boundary conditions, the engine inlet was set with flow outlet boundary conditions, and the remaining wall surfaces were set with no-slip wall boundary conditions. The results are shown in Table 1 and Figures 2-4 shown.

[0079] Among them, reverse thrust design point and slow speed are two common operating states of the engine.

[0080] Table 1 Effect of reverse thrust exhaust volute on reverse thrust exhaust back pressure

[0081] unit Reverse design point local No volute Pa 125306 102593 With volute Pa 125118 102589 Absolute value Pa 188 4 Relative value 0.15％ 0.0039％

[0082] According to the simulation results, the flow field inside the thrust reverser exhaust volute with the above-mentioned aerodynamic surface is stable and unobstructed, the streamline / exhaust airflow leaving the volute outlet can smoothly enter the ejector tube, and the impact on the thrust reverser exhaust back pressure is ≤200Pa, almost no air leakage occurs, and the exhaust effect is stable and excellent.

[0083] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed by the present invention should be covered by the scope of protection of the present invention.

Claims

1. A method for designing a two-dimensional aerodynamic profile of an aircraft engine thrust reverser exhaust volute, characterized in that: The aerodynamic profile includes, from left to right, a pressure surface, a first guide vane, a second guide vane, and a suction surface. The pressure surface and the suction surface are arcs with extended lines at the exhaust end. The first guide vane and the second guide vane are arcs. The specific steps include: S1: According to the axial length L of the engine exhaust port x Determine the arc radius R of the pressure surface 压力面 , and according to the engine exhaust angle θ 发动机 , that is, the volute intake angle θ 进气 , determine the arc tangent angle of the air inlet end of the pressure surface; S2: Determine the exhaust angle θ of the volute according to the position of the ejector tube 排气 , determine the arc tangent angle of the outlet end of the pressure surface according to the exhaust angle, that is, the extension line angle; S3: Determine the arc radius R of the suction surface according to the arc radius of the pressure surface 吸力面 The tangent angles of the air inlet and air outlet ends of the suction surface arc are the same as the tangent angles of the corresponding ends of the pressure surface arc; S4: Determine the installation positions of the pressure surface and the suction surface intake ends according to the size of the engine exhaust port; determine the virtual intake end positions of the first guide vane and the second guide vane according to the size of the engine exhaust port, and the closest intersection point of the complete circle corresponding to the guide vane arc and the plane where the engine exhaust port is located is the virtual intake end; S5: the tangent angles of the virtual air inlet and air outlet ends of the arcs of the first guide vane and the second guide vane are the same as the tangent angles of the corresponding ends of the arc of the pressure surface; S6: Draw a line connecting the center of the circle corresponding to the pressure surface arc and the center of the circle corresponding to the suction surface arc, and draw perpendicular lines to the tangents of the volute intake angle from the virtual intake ends of the first guide vane and the second guide vane, respectively. The intersection of the perpendicular lines and the connecting lines is the center position of the circle corresponding to the arc of the first guide vane and the second guide vane, thereby determining the radius of the first guide vane and the second guide vane; S7: removing a portion of each of the first guide vane and the second guide vane from the virtual air inlet end to obtain an actual air inlet end, that is, to obtain a final aerodynamic profile; Among them, the engine exhaust angle θ 发动机 and θ 进气 is the angle with the vertical direction, the volute exhaust angle θ 排气 It is the angle with the horizontal direction, with the counterclockwise direction as positive and the clockwise direction as negative; the left and right direction is the axial direction X, and the direction perpendicular to the paper is the circumferential direction Y.

2. The design method according to claim 1, characterized in that: The arc extension line of the suction surface is ≥150mm; After determining the end point of the suction surface arc extension line, draw a perpendicular line from this point to the suction surface arc extension line. The intersection of the perpendicular line and the pressure surface arc extension line is the end point of the pressure surface arc extension line.

3. The design method according to claim 1, characterized in that: For any point of the engine exhaust port, the centers of the arcs corresponding to the pressure surface, the first guide vane, the second guide vane, and the suction surface are located on the same side of the vertical line and the four points are collinear; the four centers of the circles and the engine exhaust direction are located on the opposite side of the vertical line.

4. The design method according to claim 1, characterized in that: In step S1, R 压力面 The method of determining is to take twice the axial length L of the engine exhaust port x The distance upward or downward shall be rounded to the nearest integer multiple of 100 mm; 2L x When the value is an integer multiple of 100mm, both the closest value upward and the closest value downward meet the design requirements, and there is no need to compare the closest value upward and the closest value downward with 2L. x The size of the difference between .

5. The design method according to claim 1, characterized in that: θ 发动机 is 30°~50°, θ 排气 It is -10°~-20°.

6. The design method according to claim 1, characterized in that: In step S3, R 吸力面 The method to determine R is: 吸力面 =R 压力面 -3*(100~150).

7. The design method according to claim 1, characterized in that: The installation position of the pressure surface air inlet end is located 110 to 130 mm outside the left edge of the engine exhaust port, and the installation position of the suction surface air inlet end is located outside the right edge of the engine exhaust port, and is symmetrical to the installation position of the pressure surface air inlet end; the virtual air inlet end position of the first guide vane overlaps with the left edge of the engine exhaust port; the virtual air inlet end position of the second guide vane overlaps with the right edge of the engine exhaust port.

8. The design method according to claim 1, characterized in that: In step S7, the removal length of the first guide plate or the second guide plate is 80-100 mm, and the removal lengths of the two are the same.

9. A three-dimensional aerodynamic surface, characterized in that: The three-dimensional aerodynamic profile is obtained by circumferentially expanding the two-dimensional aerodynamic profile designed by the design method according to any one of claims 1 to 8; The circumferential lengths of the pressure surface, the first guide vane, the second guide vane and the suction surface are the same and not less than the circumferential length L of the engine exhaust port. Y .

10. An aircraft engine thrust reverse exhaust volute, characterized in that: The exhaust volute includes the three-dimensional aerodynamic surface according to claim 9; The exhaust volute further comprises two front and rear restraint surfaces, the aerodynamic profile is fixed in the middle of the restraint surfaces, and the aerodynamic profile and the restraint surfaces together constitute a box-type aircraft engine reverse thrust exhaust volute.

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