Rapid reverse design method of supersonic aircraft forebody considering any three-dimensional bending shock wave

Abstract

The invention discloses a supersonic aircraft forebody fast reverse design method considering any three-dimensional bending shock waves, and relates to near space hypersonic aircrafts. According to the supersonic aircraft precursor considering any three-dimensional bending shock wave, transverse flow which cannot be neglected by a complex three-dimensional curved surface supersonic aircraft precursor is theoretically considered by utilizing a three-dimensional bending shock wave theory and a three-dimensional bending characteristic line method, so that the designed supersonic aircraft precursor can reach an ideal lift-drag ratio; and the flow field inverse design of any known three-dimensional bending shock wave is realized. Besides, gradient information can be fully utilized through the three-dimensional bending shock wave theory and the three-dimensional bending characteristic line method, compared with a traditional osculating method, the calculation efficiency is higher, the precision is higher, the obtained basic flow field is not limited to a regular flow field any more, and a wider performance improvement space is provided for aircraft design through more free shock wave selection.

Description

Technical Field

[0001] The present invention relates to a near-space hypersonic aircraft, and in particular to a method for rapid reverse design of a supersonic aircraft forebody based on a three-dimensional bending shock wave theory and a three-dimensional bending characteristic line method and taking into account arbitrary three-dimensional bending shock waves. Background Art

[0002] The development of near-space vehicles involves national security and the peaceful use of space, and is one of the focuses of the current international competition for space technology. World powers represented by the United States and Russia are vigorously promoting their own hypersonic flight development programs (Joseph, MH, James SMRichard CM, The X-51A Scramjet Engine Flight Demonstration Program, 15 thAIAA International Space Planes and Hypersonic Systems and Technologies Conference, 2008). When air flows through shock waves, the pressure can rise rapidly. Since lift is the product of surface pressure difference, pressure jump is a huge advantage in the design of supersonic aircraft. Therefore, supersonic aircraft that provide lift through shock wave supercharging are also called waveriders. Waveriders will be an ideal means of transportation for future long-distance travel and space exploration. In 1959, Nonweiler first generated a waverider from a typical inviscid two-dimensional basic flow field (Nonweiler, TRF, "Aerodynamic Problems of Manned Space Vehicles," The Aeronautical Journal, Vol. 63, No. 585, 1959, pp. 521–528). As shock wave theory develops from two-dimensional to axisymmetric, waverider theory also expands from two-dimensional basic flow fields to axisymmetric basic flow fields. In 1980, Rasmussen designed a waverider based on the inviscid hypersonic small disturbance theory using a conical flow field (Rasmussen, and Ford, MP, "Waverider Configurations Derived from Inclined Circular and Elliptic Cones," Journal of Spacecraft and Rockets, Vol. 17, No. 6, 1980, pp. 537–545). This structure is named a cone-guided waverider after the conical basic flow field. Since then, due to the aerodynamic advantages of conical flow, many researchers have conducted extensive research on conical flow waveriders. However, due to the limitations of the design method, the shock wave generated by this cone-guided waverider must be axisymmetric, which limits the structural range of the waverider. Therefore, Sobieczky proposed the osculating waverider theory in 1995 to design waveriders with generalized shock waves (Jones, KD, Sobieczky, H., Seebass, AR, and Dougherty, FC, "Waverider design for generalized shock geometries," Journal of Spacecraft and Rockets, Vol. 32, No. 6, 1995, pp. 957–963.). The core idea is to decompose the three-dimensional flow into a series of two-dimensional or axisymmetric tangent flows.In China, You Yancheng and others first proposed the dual waverider theory to integrate internal and external flows based on the kissing waverider theory (Li, YQ, Shi, CG, Zheng, XG, and You, YC, "Dual Waverider to Integrate External and Internal Flows," JOURNAL OF AIRCRAFT, 2019.).

[0003] Although significant progress has been made in the field of hypersonic waverider research, and component performance is constantly improving. However, to date, even the tangent waverider still uses an axisymmetric reference flow field, and then uses streamline tracking technology to obtain the corresponding profile. However, the three-dimensional waverider obtained based on the axisymmetric reference flow field does not have lateral flow, only directional flow. However, studies have shown that in the case of tangent cone waveriders, the effect of lateral pressure gradient cannot be ignored (Chauffour, ML, and Lewis, MJ, "Corrected Waverider Design for Inlet Applications," 40th AIAA / ASME / SAE / ASEE Joint Propulsion Conference and Exhibit, AIAA, Fort Lauderdale, Florida, 2004, p.3405.doi:10.2514 / 6.2004-3405.). This effect becomes particularly important when the hypersonic inlet is combined with the tangent cone waverider forebody. The uneven flow field caused by the lateral pressure gradient greatly reduces the performance of the propulsion system. In order to solve this problem, Lewis (Lewis, MJ, and Chauffour, ML, "Shock-based Waverider Design with Pressure Gradient Corrections and Computational Simulations," Journal of Aircraft, Vol. 42, No. 5, 2005, pp. 1350–1352. doi: 10.2514 / 1.13027.) introduced the correction of the lateral pressure gradient to generate a more accurate waverider compression surface. However, studies have shown that the lateral pressure correction has little effect on the geometric shape and cannot completely compensate for the lateral pressure gradient. The lateral flow plays a vital role in improving the performance of the aircraft. At the same time, researchers generally use the traditional characteristic line method for the inverse design of the reference flow field, which is not only complex to program, but also has poor stability, which limits the selection range of the basic flow field and thus reduces the geometric construction range of the waverider. It can be seen that one of the problems that currently restrict the performance of the hypersonic vehicle forebody is the lack of a rapid inverse design method for the forebody of a supersonic vehicle based on the three-dimensional curved shock wave theory and the three-dimensional curved characteristic line method considering arbitrary three-dimensional curved shock waves. Summary of the invention

[0004] The purpose of the present invention is to provide a method for rapid reverse design of a supersonic vehicle forebody taking into account arbitrary three-dimensional curved shock waves in order to address the above-mentioned technical problems existing in the prior art; by accurately specifying the three-dimensional curved shock waves and combining advanced flow parameter solution and flow field reconstruction technology, efficient and accurate aircraft forebody geometry design can be achieved.

[0005] The invention obtains a supersonic vehicle forebody configuration taking into account arbitrary three-dimensional bending shock waves based on three-dimensional bending shock wave theory and a three-dimensional bending characteristic line method; the supersonic vehicle forebody configuration is provided with a lower compression profile, an upper profile, and a leading edge profile; the lower profile of the supersonic vehicle forebody configuration and the upper profile of the supersonic vehicle forebody configuration are transitioned by a complex curved surface shock waverider leading edge profile.

[0006] The method for rapid reverse design of a supersonic vehicle forebody considering arbitrary three-dimensional bending shock waves of the present invention comprises the following steps:

[0007] 1) Specify any three-dimensional curved shock wave according to the design requirements; in order to better match the subsequent air inlet, specify the ICC curve (Inlet Capture Curve) and FCT (Flow Capture Tube) of the arbitrary three-dimensional curved shock wave in detail in the design plane to ensure that it matches the subsequent air inlet design; solve the center of curvature of each point on the ICC curve, and form multiple pseudo planes perpendicular to the design plane by the center of curvature and the corresponding points on the ICC curve; use spline curves with different parameters on each pseudo plane to give the shape of the incident shock wave, thereby realizing an arbitrary three-dimensional curved shock wave that meets the requirements of the subsequent air inlet;

[0008] 2) Flow parameter solution and verification: Use three-dimensional shock-surface-based curved shock theory (3D-SCST) to solve the zero-order and first-order flow parameters near the shock surface; use the three-dimensional method of curved-shockcharacteristics (3D-MOCC) to solve the zero-order and first-order flow parameters of each pseudo-plane along the plane direction and perpendicular to the plane direction, including higher-order flow characteristics; perform preliminary numerical simulations to verify the effectiveness of the 3D-SCST and 3D-MOCC methods, and adjust the theoretical parameters according to the simulation results;

[0009] 3) Flow field reconstruction and compression surface design: Based on the solved flow parameters, the flow field is reconstructed to obtain the entire three-dimensional flow field to ensure the continuity and stability of the flow field; according to the flow field reconstruction results, a compression surface that can generate a specified three-dimensional curved shock wave is designed;

[0010] 4) Design of the geometry of the forebody of the vehicle: Based on the compression surface, construct the geometry of the upper surface of the forebody of the supersonic vehicle according to the design requirements (such as aerodynamic performance, material properties, manufacturing process, etc.); rationally design the lower surface of the forebody of the vehicle to ensure coordination with the upper surface while meeting the requirements of aerodynamic stability and structural strength; connect the upper and lower surfaces to form a complete geometry of the forebody of the supersonic vehicle, and conduct preliminary geometric verification.

[0011] In step 2), the gradient information provided by the three-dimensional curved shock wave theory or the three-dimensional curved characteristic line method speeds up the solution time of the entire three-dimensional flow field.

[0012] Before specifying any three-dimensional curved shock wave according to design requirements, the design goals and optimization criteria can be clarified first: determine the overall performance requirements of the aircraft, including maximum speed, range, maneuverability, fuel efficiency, etc.; set specific design goals and optimization criteria, such as minimizing shock wave drag, maximizing lift-to-drag ratio, meeting specific flight envelopes, etc.

[0013] The advantages of the present invention are: the forebody of a supersonic aircraft considering any three-dimensional curved shock wave utilizes the three-dimensional curved shock wave theory and the three-dimensional curved characteristic line method to theoretically consider the lateral flow that cannot be ignored in the forebody of a complex three-dimensional curved supersonic aircraft, thereby ensuring that the designed forebody of the supersonic aircraft can achieve an ideal lift-to-drag ratio, and realizing the inverse design of the flow field of any known three-dimensional curved shock wave. In addition, the three-dimensional curved shock wave theory and the three-dimensional curved characteristic line method can make full use of gradient information, and have higher computational efficiency and higher accuracy than the traditional kiss-cut method. The basic flow field obtained is no longer limited to the regular flow field, and a wider performance improvement space is provided for aircraft design through more free shock wave selection. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the ICC curve, FCT curve and the center of curvature of each corresponding point in the design plane.

[0015] Figure 2 It is a schematic diagram of a three-dimensional bending shock wave.

[0016] Figure 3 It is a pseudo-plane schematic diagram based on three-dimensional curved shock waves.

[0017] Figure 4 It is a schematic diagram of three-dimensional flow field solution.

[0018] Figure 5 It is a schematic diagram of the compression profile of a given complex three-dimensional curved shock wave.

[0019] Figure 6 It is a schematic diagram of the overall structure of the aircraft forebody.

[0020] The marks in the figure are: 1 represents the ICC curve, 2 represents the FCT curve, 3 represents the pseudo plane, 4 represents the center of curvature corresponding to each point on the ICC curve, 5 represents the two-dimensional shock wave curve, 6 represents the three-dimensional curved shock wave, 7 represents the pseudo streamline, 8 represents the pseudo characteristic line, 9 represents the compression surface of the lower part of the supersonic aircraft forebody, and 10 represents the compression surface of the upper part of the supersonic aircraft forebody. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the following embodiments will further illustrate the present invention in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0022] The rapid reverse design method of supersonic vehicle forebody considering arbitrary three-dimensional bending shock wave based on three-dimensional bending shock wave theory and three-dimensional bending characteristic line method is used to obtain the following Figure 6 The supersonic vehicle forebody shown is composed of a lower compression profile 9, an upper compression profile 10 and a leading edge capture profile (FCT) 2. The lower compression profile 9 and the upper compression profile 10 intersect at the leading edge capture profile 2 of the forebody.

[0023] The main implementation steps of the rapid reverse design method of supersonic vehicle forebody considering arbitrary three-dimensional bending shock wave based on three-dimensional bending shock wave theory and three-dimensional bending characteristic line method include:

[0024] (1) Specify any three-dimensional curved shock wave 6 according to the design requirements. Figure 1 and 2 As shown, in order to better match the subsequent inlet, the ICC curve 1 (Inlet Capture Curve) and FCT curve 2 (Flow Capture Tube) of any three-dimensional curved shock wave are specified in the design plane, and the center of curvature 4 of each point on the ICC curve is solved. The center of curvature point 4 and the corresponding point on the ICC curve constitute multiple pseudo planes 3 perpendicular to the design plane, and the incident shock wave 5 is given by spline curves with different parameters on each pseudo plane 3. In this way, a complex three-dimensional curved shock wave 6 that meets the requirements of the subsequent inlet is realized.

[0025] (2) Use three-dimensional shock-surface-based curved shock theory (3D-SCST) to solve the zero-order and first-order flow parameters near the shock surface. The governing equations of the three-dimensional curved shock theory are as follows, where p is pressure, ρ is density, T is temperature, Vm is the velocity along the shock surface, Vn is the velocity perpendicular to the shock surface, γ is the specific heat ratio, R is the gas constant, and κ nm , κ nl , κ gl , κ gm and τ gm is the curvature of the shock wave surface.

[0026] Flow field relationship:

[0027] Mass equation

[0028]

[0029] Momentum equation

[0030]

[0031] Energy equation

[0032]

[0033] Equation of state

[0034]

[0035] Shock wave relationship:

[0036] Mass equation

[0037]

[0038] Momentum equation

[0039]

[0040] Velocity equation

[0041] Energy equation

[0042]

[0043] (3) Figure 3As shown in Figure 1, the three-dimensional method of curved-shock characteristics (3D-MOCC) is used to solve the zero-order and first-order flow parameters of each pseudo plane 3 along the plane direction and perpendicular to the plane direction. The specific solution process is as follows: Figure 4 : In the pseudo plane 3, the initial values ​​of the zero-order and first-order flow parameters in the pseudo plane are solved by using the pseudo streamlines 7 and pseudo characteristic lines 8, and the flow field is iterated transversely in each pseudo plane 3 until the flow field converges. The control equations of the above initial value solution and transverse iteration are as follows, where P and D are the pressure gradient in the pseudo plane 3, W is the pressure gradient perpendicular to the pseudo plane 3, V is the velocity vector in the pseudo plane 3, w is the velocity vector perpendicular to the pseudo plane 3, δ is the airflow deflection angle, θ is the shock wave angle, and μ is the Mach angle.

[0044]

[0045] (4) Figure 5 As shown, the flow field reconstruction obtains the entire three-dimensional flow field, and obtains the compression profile 9 of the lower part of the supersonic vehicle forebody that generates the specified three-dimensional bending shock wave.

[0046] (5) Figure 6 As shown, the upper compression profile 10 of the hypersonic vehicle forebody is constructed based on the lower compression profile 9 of the supersonic vehicle forebody according to the design requirements; the upper and lower surfaces are connected to form a complete supersonic vehicle forebody geometry.

[0047] After the design is completed, the design parameters can be further iterated and optimized using optimization algorithms (such as genetic algorithms, gradient descent methods, etc.) to meet the design goals and optimization criteria. Adjust the design parameters according to the optimization results, and re-solve the flow parameters, reconstruct the flow field, and design the geometric shape. Conduct multi-physics field coupling analysis to consider the impact of factors such as heat conduction, structural mechanics, and electromagnetics on the performance of the aircraft. Evaluate the safety, reliability, and durability of the aircraft to ensure that it meets flight requirements. Conduct wind tunnel tests to verify the aerodynamic performance and stability of the aircraft forebody.

[0048] Experiments show that the supersonic vehicle forebody generated by this design method taking into account arbitrary three-dimensional curved shock waves uses the three-dimensional curved shock wave theory and the three-dimensional curved characteristic line method to theoretically consider the lateral flow that cannot be ignored in the supersonic vehicle forebody, thereby ensuring that the designed supersonic vehicle forebody taking into account arbitrary three-dimensional curved shock waves can achieve an ideal lift-to-drag ratio and realize the flow field inverse design of known three-dimensional curved shock waves. In addition, the three-dimensional curved shock wave theory and the three-dimensional curved characteristic line method can make full use of gradient information, and have higher calculation efficiency and higher accuracy than the traditional kiss-cut method. The basic flow field obtained is no longer limited to the regular flow field, and a wider performance improvement space is provided for aircraft design through more free shock wave selection.

[0049] The above embodiments are only preferred embodiments of the present invention and cannot be considered to limit the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the present invention.

Claims

1. A rapid reverse design method for a supersonic vehicle forebody considering arbitrary three-dimensional curved shock waves, characterized in that The following steps are involved: 1) Specify any three-dimensional curved shock wave according to design requirements: In order to better match the subsequent air inlet, the ICC curve and FCT of the arbitrary three-dimensional curved shock wave are specified in detail in the design plane to ensure that it matches the subsequent air inlet design; solve the center of curvature of each point on the ICC curve, and form multiple pseudo planes perpendicular to the design plane by the center of curvature and the corresponding points on the ICC curve; use spline curves with different parameters on each pseudo plane to give the shape of the incident shock wave, thereby realizing an arbitrary three-dimensional curved shock wave that meets the requirements of the subsequent air inlet; 2) Flow parameter solution and verification: Use the three-dimensional curved shock wave theory 3D-SCST to solve the zero-order and first-order flow parameters near the shock wave surface; use the three-dimensional curved characteristic line method 3D-MOCC to solve the zero-order and first-order flow parameters of each pseudo-plane along the plane direction and perpendicular to the plane direction; perform preliminary numerical simulations to verify the effectiveness of the 3D-SCST and 3D-MOCC methods, and adjust the theoretical parameters according to the simulation results; 3) Flow field reconstruction and compression surface design: Based on the solved flow parameters, the flow field is reconstructed to obtain the entire three-dimensional flow field to ensure the continuity and stability of the flow field; According to the flow field reconstruction results, a compression surface capable of generating a specified three-dimensional curved shock wave is designed; 4) Design of the geometry of the forebody of the vehicle: Based on the compression surface, construct the geometry of the upper surface of the forebody of the supersonic vehicle according to the design requirements; rationally design the lower surface of the forebody of the vehicle to ensure coordination with the upper surface while meeting the requirements of aerodynamic stability and structural strength; connect the upper and lower surfaces to form a complete geometry of the forebody of the supersonic vehicle, and conduct preliminary geometry verification.

2. The method for rapid reverse design of a supersonic vehicle forebody considering arbitrary three-dimensional bending shock waves as claimed in claim 1, characterized in that In step 2), the gradient information provided by the three-dimensional curved shock wave theory or the three-dimensional curved characteristic line method speeds up the solution time of the entire three-dimensional flow field.

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