A hypersonic waverider forebody-internal turn inlet integrated design method

Abstract

The application provides a hypersonic waverider forebody-internal turning inlet integrated design method, which comprises the following steps: step 1: based on a given inlet design condition, an internal compression reference flow field is designed and obtained; step 2: based on a given free stream design condition, an external compression reference flow field is designed and obtained; step 3: the reference flow fields obtained in steps 1 and 2 are corrected for viscosity to obtain a corrected axisymmetric configuration and a corresponding corrected configuration of the inviscid flow field; step 4: based on the external compression reference flow field obtained in step 2 and the corrected inviscid external compression reference flow field obtained in step 3, a waverider forebody is designed and obtained; and step 5: based on the internal compression reference flow field obtained in step 1, the corrected inviscid internal compression reference flow field obtained in step 3 and the waverider forebody obtained in step 4, a hypersonic waverider forebody-internal turning inlet integrated configuration is designed and obtained. The application can effectively improve the aerodynamic performance of the hypersonic waverider forebody-internal turning inlet integrated configuration.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of computational fluid dynamics and aircraft aerodynamic design, and is mainly applied to wide-speed-range aircraft design, in particular to a hypersonic waverider forebody-inward-turning inlet integrated design method. BACKGROUND

[0002] In the future, low-cost space-to-ground and hypersonic travel are new trends in the field of aerospace. In view of the new trends, it is urgent to develop wide-speed-range, horizontal take-off and landing, and reusable long-range hypersonic cruise aircraft (such as HTV-3X, SR-72 aircraft). Unlike traditional space shuttles and reentry missiles, such aircraft mainly use air-breathing scramjet engines or combined engines. At the same time, the body of the reusable aircraft is highly coupled with the scramjet engine. The forebody and the afterbody are not only the main aerodynamic surface, but also the external compression surface of the engine inlet and the expansion surface of the tail nozzle, and the stress is complex. The integrated aerodynamic design directly affects the aerodynamic characteristics of the aircraft and the performance of the engine.

[0003] The inlet, as a main component of the engine, its selection will directly determine the forebody / inlet integrated design. The internal and external flow coupling of the axisymmetric inlet is weak, and the technology is mature. The two-dimensional inlet is easy to realize integrated design, but the compression efficiency of these two inlets is limited, and they are mostly suitable for hypersonic cruise missiles, such as the HyFly, X-51A of the United States, and the "Zircon" hypersonic cruise missile of Russia. The three-dimensional inward-turning inlet has high compression efficiency and strong inlet capture capability, and is easy to match with a circular cross-section combustion chamber, which is a better choice for long-range hypersonic cruise aircraft. Therefore, the integrated design of the waverider forebody-inward-turning inlet is an important research direction in the future.

[0004] According to the relative position of the forebody and the inlet, the current waverider forebody-inward-turning inlet integrated design methods include head inlet, two-side inlet, back inlet, and belly inlet. The independent inlet scheme of the head inlet (CN201610126144) and the two-side inlet (CN201910799830) directly faces the incoming flow and needs a large enough capture area to meet the flow demand, which increases the size, immersion area, and weight of the propulsion system. The inlet scheme with forebody pre-compression, such as the back inlet (CN201910648043) and the belly inlet (CN201510219732), can effectively reduce the inlet area by utilizing the pre-compression effect of the forebody, thereby reducing the immersion area and weight of the propulsion system. Among them, the back inlet scheme does not fully utilize the pre-compression effect of the forebody, so the integrated method with forebody pre-compression is mostly the belly inlet scheme.

[0005] The belly air intake integration with precursor pre-compression can be realized by the common reference flow field method (CN201410344926, CN201610064525, CN201910325410) or the reference flow field intersection method (CN202111552197, CN202110516537). Although these methods effectively realize the integration design of the wave-riding precursor-inner rotating inlet, there are still some deficiencies. On the one hand, the reference flow field adopted by the wave-riding precursor and the inner rotating inlet is mostly obtained by positive design (i.e., solving the flow field with known wall surface), compared with the reverse design (solving the wall surface shape with known flow distribution), the performance of the positive design reference flow field cannot reach the optimum. On the other hand, the reference flow field used in the integration design is obtained by solving the characteristic line method, ignoring the viscosity of the flow field or using a relatively rough viscosity correction such as a flat plate boundary layer. The above deficiencies of the reference flow field will restrict the aerodynamic performance of the wave-riding precursor-inner rotating inlet integrated configuration. SUMMARY

[0006] In view of the deficiencies of the prior art, the present application provides a hypersonic wave-riding precursor-inner rotating inlet integrated design method, which gives a flow field parameter distribution, obtains an inner compression reference flow field under the design working condition, then solves the inviscid reference flow field by solving the flow equation using computational fluid dynamics (CFD) technology, and modifies based on the axisymmetric boundary to better consider the viscous effect. This method can effectively solve the problems existing in the above integrated design.

[0007] The present application is realized by the following technical solutions:

[0008] The hypersonic wave-riding precursor-inner rotating inlet integrated design method comprises the following steps:

[0009] Step 1: Design the inner compression reference flow field;

[0010] Based on the given inlet entrance design working condition and flow parameter distribution law, the inner compression reference flow field is obtained by solving the characteristic line method;

[0011] Step 2: Design the outer compression reference flow field;

[0012] Based on the given free stream design working condition, the outer compression reference flow field is obtained by solving the characteristic line method;

[0013] Step 3: Based on the high-precision flow simulation results of CFD, the obtained inner and outer compression flow fields are viscously modified;

[0014] The inner compression and outer compression reference flow fields obtained in steps 1 and 2 are viscously modified to obtain the inviscid flow field of the modified inner compression axisymmetric configuration, the outer compression axisymmetric configuration and the corresponding modified configuration;

[0015] Step 4: generating a waverider forebody;

[0016] Based on the outer compression reference flow field obtained in Step 2 and the inviscid outer compression reference flow field corrected in Step 3, a waverider forebody is designed;

[0017] Step 5: generating an integrated configuration;

[0018] Based on the inner compression reference flow field designed in Step 1, the inviscid inner compression reference flow field corrected in Step 3 and the waverider forebody designed in Step 4, a hypersonic waverider forebody-inner turn inlet integrated configuration is designed.

[0019] Further, the Step 1 comprises the following sub-steps:

[0020] Step 1.1: setting a design condition: an altitude H inlet , a Mach number Ma inlet , an angle of attack a inlet , calculating a Reynolds number Re inlet according to H inlet and Ma inlet , wherein the subscript inlet represents an inlet of the inlet;

[0021] Step 1.2: giving a function model of a flow parameter distribution law of an inner compression curved wall surface ICS: a Mach number distribution Ma -ICS (x), a coordinate system adopting a cylindrical coordinate system wherein x is a flow direction coordinate, r is a radial coordinate, is an included angle between the r radial direction and the z direction; at the same time, a function model of a flow parameter distribution law of a reflected shock wave RS: a total pressure recovery coefficient distribution s RS (r) is given;

[0022] Step 1.3: according to the flow parameter distribution law given in Step 1.2, an axisymmetric inner contraction flow field is solved by using a characteristic line method as the inner compression reference flow field; the characteristic line method specifically refers to: solving an equation group composed of a characteristic line equation and a compatibility equation of two-dimensional supersonic inviscid flow by using a second-order Euler prediction and correction method, and a mathematical expression of the equation group is as follows:

[0023]

[0024] Further, the Step 2 comprises the following sub-steps:

[0025] Step 2.1: setting an incoming flow altitude H ∞ , an incoming flow Mach number Ma ∞ , a half-cone angle d;

[0026] Step 2.2: According to the given half-cone angle δ, the wall coordinates (x, r) of the axisymmetric outer compression are generated, and according to the wall coordinates and the inflow parameters, the axisymmetric outer compression straight cone flow field and the shock angle β are solved by using the method of characteristics;

[0027] Step 2.3: At any position in the x positive direction, the flow field distribution after the leading edge shock LS of the outer compression straight cone flow field is intercepted, and the Mach number Ma, pressure P, temperature T, flow angle θ distribution are obtained, and the position average along R direction is carried out on the obtained flow field distribution, and the post-wave parameters Ma LS , P LS , T LS , θ LS and Reynolds number Re LS are obtained;

[0028] Step 2.4: Determine whether the error between Ma LS and Ma inlet is within the set convergence accuracy, whether the error between Re LS and Re inlet is within the set convergence accuracy, if not within the set convergence accuracy, adjust Ma ∞ and half-cone angle δ, repeat steps 2.2-2.3 until convergence, and obtain the outer compression reference flow field of the matching inner compression flow field inlet parameters Ma inlet and Re inlet .

[0029] Further, the step 3 comprises the following sub-steps:

[0030] Step 3.1: Extract the wall surface pressure rise P IC (x) and P OC (x) of the inner and outer compression reference flow fields obtained in steps 1 and 2, and the subscript IC represents the inner compression and OC represents the outer compression;

[0031] Step 3.2: According to the inflow conditions (H inlet , Ma inlet ) and the outer compression reference flow field inflow conditions (H ∞ , Ma ∞ ) of the inner and outer compression reference flow fields, respectively, solve the Reynolds time-averaged NS equation for the inner and outer compression axisymmetric configuration, respectively, to obtain the viscous inner compression reference flow field and the wall surface pressure rise P IC-viscous-i (x) under the reference flow field, and the viscous outer compression reference flow field and the wall surface pressure rise P OC-viscous-i (x) under the reference flow field;

[0032] Step 3.3: Determine whether the difference between P IC-viscous-i (x) and P IC (x) is within the set range, and whether P OC-viscous-i (x) and POC (x) is within the set range, it is considered to be converged, and the correction is ended; if it is not within the set range, the inner compression wall surface profile and the outer compression wall surface profile are corrected in the following two cases, which are as follows:

[0033] Case 1: if the inner compression P IC-viscous-i (x) is greater than P IC (x) or the outer compression P OC-viscous-i (x) is greater than P OC (x), then:

[0034] (1) according to the inflow conditions (H inlet , Ma inlet ) of the inner compression reference flow field and the inflow conditions (H ∞ , Ma ∞ ) of the outer compression reference flow field, the inviscid Euler equation is solved for the inner and outer compression axisymmetric configurations, respectively, to obtain the inviscid inner compression reference flow field and the inviscid outer compression reference flow field;

[0035] (2) the boundary layer displacement thickness δ* of the reference flow field is calculated;

[0036] Firstly, the boundary layer thickness of the viscous inner compression reference flow field and the viscous outer compression reference flow field obtained in step 3.2 is calculated, and the specific process is as follows: the streamwise velocity distribution is obtained by intercepting the streamwise velocity distribution at different x-direction positions in the viscous inner compression reference flow field and the viscous outer compression reference flow field calculated in step 3.2, and the slope between two points on the streamwise velocity profile is calculated based on the obtained streamwise velocity profile by using the following formula:

[0037]

[0038] When the obtained slope satisfies |K i+1 |>10*|K i |, let r δ =r i+1 , then the boundary layer thickness δ=r δ -r0;

[0039] Secondly, based on the boundary layer thickness of the viscous inner compression reference flow field and the viscous outer compression reference flow field, the new r-direction coordinate r δ* after the boundary layer displacement thickness δ* is applied to the boundary layer thickness δ at different x-direction positions is calculated by using the following formula: in the formula, the subscript inv represents the inviscid reference flow field calculated in (1) of case 1, and the subscript vis represents the viscous reference flow field calculated in step 3.2;

[0040]

[0041] Further calculation obtains the axisymmetric boundary layer displacement thickness as follows:

[0042] Inner compression displacement thickness:

[0043] Outer compression displacement thickness:

[0044] (3) At different x-direction positions, the calculated inner compression displacement thickness is applied to the inner compression wall surface to make a positive r-axis offset, and the calculated outer compression displacement thickness is applied to the outer compression wall surface to make a negative r-axis offset;

[0045] Case 2: If the inner compression P IC-viscous-i (x) < P IC (x) or the outer compression P OC-viscous-i (x) < P OC (x), then:

[0046] At different x-direction positions, 1 / 2 of the displacement thickness δ * (x) calculated in the last iteration in which case 1 is entered is applied to the inner compression wall surface to make a negative r-axis offset, and 1 / 2 of the displacement thickness δ * (x) calculated in the last iteration in which case 1 is entered is applied to the outer compression wall surface to make a positive r-axis offset;

[0047] Step 3.4: Repeat step 3.2 and step 3.3 until convergence is achieved, and finally obtain a modified axisymmetric configuration and a corresponding modified inviscid flow field.

[0048] Further, the step 4 comprises the following sub-steps:

[0049] Step 4.1: Design a front edge front projection profile FCT on the base circle;

[0050] Step 4.2: From the base circle, extend along the reverse incoming flow direction to generate an upper surface of the waverider, with the FCT profile obtained in step 4.1 as the contour, and intersect with the leading edge shock wave surface LS designed in step 2 to obtain a leading edge profile of the waverider;

[0051] Step 4.3: From the leading edge profile obtained in step 4.2 as the contour, extend along the flow direction to perform streamline tracing in the inviscid outer compression reference flow field modified in step 3 until the base circle of the leading edge shock wave surface LS, and generate a waverider surface, i.e. a lower surface of the waverider, according to the streamlines; combine the upper surface and the lower surface of the waverider to obtain a waverider forebody.

[0052] Further, the step 5 comprises the following sub-steps:

[0053] Step 5.1: Set the required flow m to be captured, in the symmetry plane, along the leading edge shock wave surface LS, move the lower lip point of the inner compression incident shock wave surface IS designed in step 1 to any position along the leading edge shock wave surface LS, to determine the initial position of the lower lip in the X direction;

[0054] Step 5.2: Rotate the inner compression incident shock wave surface IS designed in step 1 along the rotation axis by an angle |θ LS | to match the flow direction θ LS after the leading edge shock wave surface LS;

[0055] Step 5.3: Scale the inviscid inner compression reference flow field designed in step 1 by a set ratio, and the inner compression shock wave surface IS intersects the leading edge shock wave surface LS and the waverider surface to obtain the inlet capture inlet FCI, and the capture flow m is calculated according to the capture area S, H ∞ , Ma ∞ ;

[0056] Step 5.4: Determine whether the difference between the calculated capture flow and the set required capture flow is within the set convergence accuracy, if not, adjust the lower lip point position and the scaling ratio, repeat steps 5.2-5.3 until the flow requirement is met, and obtain the inlet capture inlet that meets the flow requirement;

[0057] Step 5.5: Take the inlet capture inlet obtained in step 5.4 as the contour and start in the streamwise direction, perform streamline tracing in the inviscid inner compression reference flow field corrected in step 3 to the bottom circle, and generate the inner turning inlet surface according to the streamlines;

[0058] Step 5.6: Take the inlet capture inlet obtained in step 5.4 as the contour and start in the streamwise direction, perform streamline tracing in the inviscid outer compression reference flow field corrected in step 3 to the bottom circle, and generate the outer cover according to the streamlines;

[0059] Step 5.7: Combine the waverider forebody obtained in step 4, the inner turning inlet obtained in step 5.5, and the outer cover obtained in step 5.6 to generate an integrated configuration, and round the leading edge of the configuration according to the set rounding radius to obtain the final hypersonic waverider forebody-inner turning inlet integrated configuration.

[0060] Advantages

[0061] The application provides a hypersonic waverider forebody-internal turn inlet integrated design method, compared with an existing method, an internal compression reference flow field is obtained by adopting a positive design method (a wall surface shape is directly given), the method is obtained by solving the wall surface shape by giving a flow parameter distribution in the flow field, because the total pressure distribution after a reflection shock wave is given, the method can control the internal compression reference flow field total pressure loss to be minimum; in addition, the existing method is mostly inviscid design or adopts viscous empirical correction based on a flat plate boundary layer, the method is based on an axisymmetric boundary layer theory, solves displacement thickness by adopting a high-precision flow simulation method based on CFD to perform viscous correction, the correction is closer to the actual situation, and can reduce the gap between actual flow compression efficiency and capture efficiency and the expected design; based on the above two points, the pressure rise, total pressure recovery and flow capture efficiency of the integrated configuration obtained by the method can be effectively improved. BRIEF DESCRIPTION OF DRAWINGS

[0062] Figure 1 It is a basic flow schematic diagram of the hypersonic waverider forebody-internal turn inlet integrated design method of the embodiment of the application;

[0063] Figure 2 It is a schematic diagram of the cylindrical coordinate system and the rectangular coordinate system adopted by the embodiment of the application;

[0064] Figure 3 It is a schematic diagram of the internal compression reference flow field of the embodiment of the application;

[0065] Figure 4 It is the internal compression reference flow field of the embodiment of the application, wherein the wall surface Mach number distribution and the reflection shock wave total pressure recovery coefficient distribution are given;

[0066] Figure 5 It is a schematic diagram of the external compression reference flow field of the embodiment of the application;

[0067] Figure 6 It is the external compression reference flow field of the embodiment of the application, wherein the internal compression reference flow field design working condition is matched; Figure 3

[0068] Figure 7 It is the flow field distribution of different X stations in the external compression reference flow field of the embodiment of the application;

[0069] Among them, Figure 7 (a) is a station schematic diagram, Figure 7 (b) is a Mach number Ma distribution, Figure 7 (c) is a pressure P distribution, Figure 7 (d) is a density p distribution, Figure 7 (e) is a flow angle theta (radian) distribution;

[0070] Figure 8 ​A viscosity correction flow process for a reference flow field of an embodiment of the present application;

[0071] Figure 9 A streamline velocity type diagram used in an embodiment of the present application;

[0072] wherein, Figure 9 (a) is a streamline velocity distribution type of a viscous inner compression reference flow field, Figure 9 (b) is a streamline velocity distribution type of a viscous outer compression reference flow field;

[0073] Figure 10 A boundary layer diagram of a viscous inner and outer compression flow field of an embodiment of the present application;

[0074] wherein, Figure 10 (a) is a boundary layer of a viscous inner compression reference flow field, Figure 10 (b) is a boundary layer of a viscous outer compression reference flow field;

[0075] Figure 11 An inner compression wall surface correction diagram of an embodiment of the present application;

[0076] Figure 12 An outer compression wall surface correction diagram of an embodiment of the present application;

[0077] Figure 13 A viscous correction result of an inner compression reference flow field in an embodiment of the present application;

[0078] wherein, Figure 13 (a) is an inner compression curved wall surface configuration, Figure 13 (b) is an inner compression curved wall surface pressure coefficient distribution;

[0079] Figure 14 A viscous correction result of an outer compression reference flow field in an embodiment of the present application;

[0080] wherein, Figure 14 (a) is an outer compression curved wall surface configuration, Figure 14 (b) is an outer compression curved wall surface pressure coefficient distribution;

[0081] Figure 15 A wave-riding forebody generation diagram of an embodiment of the present application;

[0082] Figure 16 An upper surface generation diagram of a wave-riding forebody in an embodiment of the present application;

[0083] Figure 17 A wave-riding surface generation diagram of a wave-riding forebody in an embodiment of the present application;

[0084] Figure 18 A wave-riding forebody generated in an embodiment of the present application;

[0085] Figure 19 A schematic diagram for the integrated configuration of an embodiment of the present application is generated;

[0086] Figure 20 A schematic diagram for the integrated configuration of an embodiment of the present application is generated;

[0087] Figure 21 A schematic diagram for the position and size of the inner compression reference flow field relative to the outer compression reference flow field in an embodiment of the present application is generated;

[0088] Figure 22 A schematic diagram for the determination of the capture inlet of the inner turning inlet duct in an embodiment of the present application is generated;

[0089] Figure 23 A schematic diagram for the generation of the inner turning inlet duct in an embodiment of the present application is generated;

[0090] Figure 24 A schematic diagram for the generation of the inner turning inlet duct in an embodiment of the present application is generated;

[0091] Figure 25 A schematic diagram for the generation of the final integrated configuration in an embodiment of the present application is generated;

[0092] Figure 26 A comparison between the improved integrated configuration and the original integrated configuration in an embodiment of the present application is generated;

[0093] wherein, Figure 26 (a) is the improved integrated configuration obtained in an embodiment of the present application, Figure 26 (b) is the original integrated configuration without using the method of the present application;

[0094] Figure 27 The spatial flow field characteristics of the improved integrated configuration obtained by using the method of the present application in an embodiment of the present application are generated. DETAILED DESCRIPTION

[0095] In order to make the technical problems, technical solutions and beneficial effects solved by the present application more clear and understandable, and to make the personnel in the technical field better understand the present application scheme, the present application is further described and completely explained in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application.

[0096] The present embodiment utilizes a hypersonic waverider forebody-inner turning inlet integrated design method proposed by the present application, and carries out waverider forebody-inner turning inlet integrated design for a certain hypersonic vehicle, as shown in Figure 1 , including the following steps:

[0097] Step 1: Design the inner compression reference flow field, as shown in Figure 3As shown, that is, based on the given inlet design conditions and flow parameter distribution law, the characteristic line method is used to solve the internal compression reference flow field; Specifically, the following sub-steps are included:

[0098] Step 1.1: Set the design condition: altitude H inlet , Mach number Ma inlet , angle of attack α inlet , according to H inlet and Ma inlet , the Reynolds number Re inlet is calculated, wherein the subscript inlet represents the inlet of the inlet;

[0099] In this embodiment, the altitude H inlet =25km, the Mach number Ma inlet =6, the angle of attack α inlet =0, the Reynolds number Re inlet =4954154 is calculated.

[0100] Step 1.2: Given the function model of the flow parameter distribution law of the internal compression curved wall ICS: the Mach number distribution Ma -ICS (x), the coordinate system uses cylindrical coordinates Where x is the flow direction coordinate, r is the radial coordinate, is the angle between r radial and z direction; At the same time, the function model of the flow parameter distribution law of the reflected shock RS is given: the total pressure recovery coefficient distribution σ RS (r), in this embodiment, the relationship between the cylindrical coordinate system and the rectangular coordinate system used is as shown in Figure 2 ;

[0101] In this embodiment, the function model of the flow parameter distribution law of the internal compression curved wall ICS is a cubic distribution of the wall Mach number, and the specific expression is:

[0102]

[0103] a=0.4, b=-0.5, c=-1.2, d=5.5, R i =1

[0104] Wherein, the subscript ICS represents the internal compression curved wall, a, b, c, d represent constant coefficients, and R i represents the inlet radius of the internal compression flow field;

[0105] The function model of the flow parameter distribution law of the reflected shock RS is a quadratic distribution of the total pressure recovery coefficient, and the specific expression is:

[0106]

[0107] σr CB= 0.999, σr ICS = 0.97, R i = 1

[0108] wherein, σr CB is the total pressure recovery coefficient at the intersection of the reflected shock wave RS and the center body CB, σr ICS is the total pressure recovery coefficient at the intersection of the reflected shock wave RS and the inner compression curved wall ICS, the coefficients ar, br, cr are obtained in the calculation process according to the flow field, and the specific calculation formula is as follows:

[0109] ar = σr ICS - σr CB / r ICS 2 -2*r ICS *r CB +r CB 2

[0110] br = -2*ar*r CB

[0111] cr = σr CB +ar*r CB 2

[0112] wherein, the subscript ICS represents the inner compression curved wall, and the subscript CB represents the center body;

[0113] Step 1.3: According to the flow parameter distribution law given in step 1.2, an axisymmetric inner contraction flow field is obtained by using the method of characteristics as an inner compression reference flow field; the method of characteristics is specifically: the second-order Euler prediction and correction method is used to solve the equation group composed of the characteristic line equation and the compatibility equation of two-dimensional supersonic incompressible flow, and the mathematical expression of the equation group is as follows:

[0114]

[0115] In this embodiment, according to the flow parameter distribution law given in step 1.2, an axisymmetric inner contraction flow field is obtained by using the method of characteristics as shown in Figure 4 In order to verify that the method of characteristics adopted in the application is reliable, the results obtained by using Euler equation in this embodiment are compared, Figure 4 the upper half part in the figure is the result of the method of characteristics of the application, and the lower half part is the result obtained by solving Euler equation, and it can be seen from the figure that the two results are basically the same, which proves that the inner compression reference flow field obtained by using the method of characteristics in the application is reliable.

[0116] Step 2: Design the outer compression reference flow field, as shown in Figure 5 that is, based on the given free stream design working condition, the method of characteristics is used to obtain the outer compression reference flow field.

[0117] Specifically, it includes the following sub-steps:

[0118] Step 2.1: Set the incoming flow height H of the external compression reference flow field ∞ Mach number of the incoming flow ∞ δ, the semi-cone angle;

[0119] In this embodiment, the incoming flow height H of the external compression reference flow field is set. ∞ =30km, incoming Mach number Ma ∞ The variation range is 5 to 8, and the variation range of the semi-cone angle δ is 8.9° to 10°.

[0120] Step 2.2: Based on the given semi-cone angle δ, generate the axisymmetric external compression wall coordinates (x, r). Based on the wall coordinates and the incoming flow parameters, use the method of characteristics to solve for the axisymmetric external compression straight cone flow field and shock wave angle β.

[0121] Step 2.3: At any position in the positive x-direction, capture the flow field distribution behind the leading edge shock wave LS of the externally compressed straight cone flow field to obtain the Mach number Ma, pressure P, temperature T, and flow angle θ distribution. Perform position averaging along the R-direction on the obtained flow field distribution to obtain the wave-after parameter Ma. LS P LS T LS θ LS and Reynolds number Re LS ;

[0122] Step 2.4: Determine Ma LS and Ma inlet Whether the error between them is within the set convergence accuracy, Re LS and Re inlet Check if the error between them is within the set convergence accuracy. If not, adjust Ma. ∞ Given the half-cone angle δ, repeat steps 2.2 to 2.3 until convergence, to obtain the inlet parameters Ma of the matched internal compression flow field. inlet and Re inlet External compression reference flow field;

[0123] In this embodiment, finally when Ma ∞ When δ = 7.5, β = 9.9°, and β = 13.15°, the inlet parameters Ma of the matched internal compression flow field are obtained. inlet and Re inlet External compression reference flow field such as Figure 6 As shown, the Mach number Ma, pressure P, density ρ, and flow angle θ (radians) distributions at stations with m = 5, 6, 7, 8, and 9 m in the flow field are as follows: Figure 7As shown, because it is a straight cone flow field, the average parameter is consistent across different locations after averaging, which is: Ma LS =5.992, Re LS =4709744, θ LS = 8.4°, which is consistent with the intake parameters: Ma inlet =6, Re inlet =4954154. The convergence accuracy is reached, and the design condition matching is considered to be completed. The resulting flow field is used as the external compression reference flow field.

[0124] Step 3: Based on the high-precision flow simulation results from CFD, perform viscous correction on the obtained internal and external compression flow fields; that is, perform viscous correction on the internal and external compression reference flow fields obtained in Steps 1 and 2 to obtain the corrected internal compression axisymmetric configuration, external compression axisymmetric configuration, and the corresponding inviscid flow field of the corrected configuration; the correction process is as follows: Figure 8 As shown;

[0125] Specifically, it includes the following sub-steps:

[0126] Step 3.1: Extract the wall pressure rise P of the internal and external compression reference flow fields obtained in Step 1 and Step 2. IC (x) and P OC (x), where the subscript IC indicates internal compression and OC indicates external compression;

[0127] Step 3.2: Based on the inflow conditions (H) of the internal compression reference flow field respectively inlet Ma inlet ) and external compression reference flow field inflow conditions (H ∞ Ma ∞ Solving the Reynolds-averaged Navier-Stokes equations for both internal and external compression axisymmetric configurations yields the reference flow field for viscous internal compression and the wall pressure rise P under this reference flow field. IC-viscous-i (x) and the viscous external compressibility reference flow field and the wall pressure rise P under this reference flow field OC-viscous-i (x);

[0128] Step 3.3: Determine P IC-viscous-i (x) and P IC Whether the difference between (x) and P is within the set range, and P OC-viscous-i (x) and P OC Whether the difference between (x) is within the set range; if it is within the set range, it is considered convergence and the correction ends; if it is not within the set range, the inner compression wall profile and the outer compression wall profile are corrected in the following two cases, specifically:

[0129] Case 1: If internal compression P IC-viscous-i (x)>P IC (x) or external compression POC-viscous-i (x)>P OC (x), then:

[0130] (1) Based on the inflow conditions (H) of the internal compression reference flow field respectively inlet Ma inlet ) and external compression reference flow field inflow conditions (H ∞ Ma ∞ Solving the inviscid Euler equations for the inner and outer compression axisymmetric configurations yields the inviscid inner compression reference flow field and the inviscid outer compression reference flow field, respectively.

[0131] (2) Calculate the boundary layer displacement thickness δ* of the reference flow field;

[0132] First, the boundary layer thickness is calculated for the viscous internal compression reference flow field and the viscous external compression reference flow field obtained in step 3.2. Specifically, at different x-direction positions in the viscous internal compression reference flow field and the viscous external compression reference flow field calculated in step 3.2, the flow velocity distribution is extracted to obtain the flow velocity profile. In this embodiment, the flow velocity distribution profile obtained for the viscous internal compression reference flow field is as follows: Figure 9 As shown in (a), the flow velocity distribution pattern in the viscous external compressibility reference flow field is as follows: Figure 9 As shown in (b); based on the obtained flow velocity profile, the slope between two points on the flow velocity profile is calculated using the following formula:

[0133]

[0134] When the obtained slope satisfies |K i+1 |>10*|K i |When, let r δ =r i+1 Then the boundary layer thickness δ = r δ -r0;

[0135] Secondly, based on the boundary layers of the obtained viscous internal compressibility reference flow field and viscous external compressibility reference flow field, such as Figure 10 As shown, the following formula is used to calculate the new coordinates in the r-direction after applying a boundary layer displacement thickness δ* to the boundary layer thickness δ at different x-direction positions. In the formula, the subscript inv represents the inviscid reference flow field calculated in (1) of case 1, and the subscript vis represents the viscous reference flow field calculated in step 3.2.

[0136]

[0137] The axisymmetric boundary layer displacement thickness was then calculated to be:

[0138] Internal compression displacement thickness:

[0139] Outer compression displacement thickness:

[0140] (3) At different x-locations, the calculated inner compression displacement thickness is applied to the inner compression wall surface to produce a positive r-axis displacement, and the calculated outer compression displacement thickness is applied to the outer compression wall surface to produce a negative r-axis displacement, as shown in Figure 11 and Figure 12 .

[0141] Case 2: If the inner compression P IC-viscous-i (x)<P IC (x) or the outer compression P OC-viscous-i (x)<P OC (x), then:

[0142] At different x-locations, 1 / 2 of the displacement thickness δ * (x) calculated in the last iteration in which the case 1 was entered is applied to the inner compression wall surface to produce a negative r-axis displacement, and 1 / 2 of the displacement thickness δ * (x) calculated in the last iteration in which the case 1 was entered is applied to the outer compression wall surface to produce a positive r-axis displacement, as shown in Figure 11 and Figure 12 .

[0143] Step 3.4: Repeat Step 3.2 and Step 3.3 until convergence is achieved, and finally obtain the modified axisymmetric configuration and the corresponding modified inviscid flow field.

[0144] In this embodiment, the results of the viscous modification of the inner compression baseline flow field obtained in Step 1 are shown in Figure 13 , where original is the initial axisymmetric configuration, mod is the modified configuration, the mod configuration is expanded outward along the R-axis compared to the original configuration, inviscid is the wall pressure coefficient distribution obtained by the design, and mod-viscous is the viscous pressure coefficient distribution after modification, and the pressure rises of the two are basically the same.

[0145] The results of the viscous modification of the outer compression baseline flow field obtained in Step 2 are shown in Figure 14 , where original is the initial axisymmetric configuration, mod is the modified configuration, the mod configuration is contracted inward along the R-axis compared to the original configuration, inviscid is the wall pressure coefficient distribution obtained by the design, and mod-viscous is the viscous pressure coefficient distribution after modification, and the pressure rises of the two are basically the same.

[0146] Step 4: Generate a waverider forebody, i.e., based on the outer compression baseline flow field obtained in Step 2 and the modified inviscid outer compression baseline flow field in Step 3, design to obtain a waverider forebody, as shown inFigure 15 as shown in FIG. 4.1;

[0147] Specifically, the following sub-steps are included:

[0148] Step 4.1: On the bottom circle of the outer compression reference flow field X = 3 m designed in step 2, the front edge front projection profile FCT is designed, which is a three-point spline curve, and the three-point coordinates are as shown in FIG. 4.1;

[0149] In this embodiment, the FCT profile is designed on the bottom circle of the outer compression reference flow field X = 3 m designed in step 2, and the FCT profile is a three-point spline curve, and the three-point coordinates are as shown in FIG. 4.1. Figure 16

[0150] Step 4.2: Starting from the bottom circle, the FCT profile obtained in step 4.1 is used as the contour, and the extension is performed along the reverse incoming flow direction (i.e. X negative direction), to generate the upper surface of the waverider, and the intersection with the front edge shock wave surface LS designed in step 2 obtains the front edge profile of the waverider, as shown in FIG. 4.2; Figure 17

[0151] Step 4.3: The front edge profile obtained in step 4.2 is used as the contour and extended along the flow direction, and the streamline tracing is performed in the inviscid outer compression reference flow field modified in step 3 until the bottom circle of the front edge shock wave surface LS, and the traced streamlines are as shown in FIG. 4.3, and the waverider surface is generated according to the streamlines, that is, the lower surface of the waverider; and the upper surface and the lower surface of the waverider are combined to obtain the waverider forebody, as shown in FIG. 4.4. Figure 17 Figure 18

[0152] Step 5: An integrated configuration is generated, that is, based on the inner compression reference flow field designed in step 1, the inviscid inner compression reference flow field modified in step 3, and the waverider forebody obtained in step 4, a hypersonic waverider forebody-inner turning inlet integrated configuration is designed, as shown in FIG. 5 and FIG. 6; Figure 19 Figure 20

[0153] Specifically, the following sub-steps are included:

[0154] Step 5.1: Set the flow rate m to be captured, and move the lower lip point of the inner compression incident shock wave surface IS designed in step 1 to any position along the front edge shock wave surface LS in the symmetry plane to determine the initial X-direction position of the lower lip;

[0155] In this embodiment, the flow rate m to be captured is set to m = 4.22 kg / s, and the initial X-direction position of the lower lip is determined to be X = 2.25, as shown in FIG. 5.1①; Figure 21

[0156] Step 5.2: Rotate the inner compression incident shock wave surface IS obtained in step 1 along the rotation axis by an angle: |θ LS |, to match the flow direction θ LS after the front edge shock wave surface LS; in this embodiment, θ LS ​​​​​​​= 8.4°, as shown in Figure 21 in the middle ②;

[0157] Step 5.3: Scale the inviscid inner compression reference flow field obtained in step 1 by a set ratio, in this embodiment, the set ratio is 1:4, that is, the inviscid inner compression reference flow field obtained in step 1 is reduced by 4 times, as shown in Figure 21 in the middle ③, the inner compression shock wave surface IS intersects the leading edge shock wave surface LS and the waverider surface to obtain the inlet capture inlet FCI, and the capture area S, H ∞ , Ma ∞ , the capture flow rate m is calculated;

[0158] Step 5.4: Determine whether the difference between the calculated capture flow rate and the set required capture flow rate is within the set convergence accuracy, if not, adjust the lower lip point position and the scaling ratio, and repeat steps 5.2-5.3 until the flow rate requirement is met; the final inlet capture inlet obtained in step 5.4 is shown in Figure 22 ;

[0159] Step 5.5: Starting from the inlet capture inlet obtained in step 5.4 as the contour along the flow direction, perform streamline tracing in the inviscid inner compression reference flow field corrected in step 3 to the bottom circle, the traced streamlines are shown in Figure 23 , and the inner turning inlet surface is generated according to the streamlines, and the obtained inner turning inlet is shown in Figure 24 ;

[0160] Step 5.6: Starting from the inlet capture inlet obtained in step 5.4 as the contour along the flow direction, perform streamline tracing in the inviscid outer compression reference flow field corrected in step 3 to the bottom circle to generate an outer cover;

[0161] Step 5.7: Combine the waverider forebody obtained in step 4, the inner turning inlet obtained in step 5.5, and the outer cover obtained in step 5.6 to generate an integrated configuration, and perform rounding processing on the leading edge of the configuration according to a set rounding radius to obtain a final hypersonic waverider forebody-inner turning inlet integrated configuration; in this embodiment, the rounding radius is 1 mm, and the final hypersonic waverider forebody-inner turning inlet integrated configuration is shown in Figure 25 .

[0162] In this embodiment, the improved integrated configuration designed by the method of the present application is compared with the original integrated configuration as shown in Figure 26 , wherein the original integrated configuration shown in Figure 26 (b) is designed by using the prior art, and the specific method refers to the reference flow field intersection method disclosed in patent CN202111552197, and the viscous flow numerical simulation is performed on the improved integrated configuration shown in Figure 26 (a), and the Mach number spatial distribution is as shown inFigure 27 As shown, the improved integrated configuration can simultaneously achieve outer and inner wave-multiplying, which meets the design expectation.

[0163] Figure 26 (b) The original integrated configuration with the inner compression reference flow field and the axisymmetric boundary layer correction without the given flow field distribution also meets the flow requirement m=4.22 kg / s, but compared with the performance parameters of the improved integrated configuration and the original integrated configuration at the throat, as shown in Table 1, it can be seen that the improved integrated configuration is improved in terms of throat pressure rise P 喉道 / P ∞ , throat total pressure recovery coefficient σ 喉道 , throat flow coefficient m 喉道 / m, and it can be seen that the design method proposed in the application can further effectively improve the aerodynamic performance of the hypersonic wave-riding body precursor-inner rotating inlet integrated configuration.

[0164] Table 1

[0165] Configuration P 喉道 / P ∞ ]]> 喉道 ]]> ​ m 喉道 / m <!-- 10 -->]]> Improved integrated configuration 114.0412 0.4867 0.9361 Original integrated configuration 89.4103 0.4753 0.8995

[0166] Although the embodiments of the application have been shown and described above, it should be understood that the above-mentioned embodiments are exemplary and should not be construed as limiting the application, and those skilled in the art can make changes, modifications, replacements and variations to the above-mentioned embodiments without departing from the principles and purposes of the application within the scope of the application.

Claims

1. A design method for an integrated hypersonic waverider forebody-internal rotating inlet, characterized in that, Includes the following steps: Step 1: Design the internal compression reference flow field; Based on the given inlet design conditions and flow parameter distribution, the internal compression reference flow field is obtained using the method of characteristics; specifically, the following sub-steps are included: Step 1.1: Set design conditions: Altitude ,Mach number Angle of attack α inlet According to H inlet and Ma inlet Calculate the Reynolds number Re inlet The subscript inlet indicates the air intake. Step 1.2: Given a functional model of the flow parameter distribution of the internally compressed curved wall ICS: Mach number distribution Ma -ICS (x), the coordinate system is cylindrical coordinate system. Where x is the flow direction coordinate and r is the radial coordinate. Let r be the angle between the radial and z-directions; simultaneously, a functional model of the flow parameter distribution of the reflected shock wave RS is given: total pressure recovery coefficient distribution. ; Step 1.3: Based on the flow parameter distribution given in Step 1.2, the axisymmetric internal contraction flow field is obtained using the method of characteristics as the internal compression reference flow field. Specifically, the method of characteristics refers to solving a system of equations consisting of the characteristic line equations and compatibility equations for two-dimensional supersonic inviscid flow using a second-order Euler prediction and correction method. The mathematical expressions of the system of equations are as follows: ； Step 2: Design the external compression reference flow field; Based on a given free-flow design condition, the externally compressed reference flow field is obtained using the method of characteristics; specifically, the following sub-steps are included: Step 2.1: Set the inflow height of the external compression reference flow field Mach number of incoming flow Half cone angle ; Step 2.2: Based on the given semi-cone angle The axisymmetric externally compressed wall coordinates (x, r) are generated. Based on the wall coordinates and incoming flow parameters, the axisymmetric externally compressed conical flow field and shock wave angle are obtained using the method of characteristics. ; Step 2.3: At any position in the positive x-direction, capture the flow field distribution behind the leading edge shock wave LS of the externally compressed straight cone flow field to obtain the Mach number Ma, pressure P, temperature T, and flow angle θ distribution. Perform position averaging along the R-direction on the obtained flow field distribution to obtain the wave-after parameter Ma. LS P LS T LS θ LS and Reynolds number Re LS ; Step 2.4: Determine Ma LS and Ma inlet Whether the error between them is within the set convergence accuracy, Re LS and Re inlet Check if the error is within the set convergence accuracy. If not, adjust... Given the half-cone angle δ, repeat steps 2.2 to 2.3 until convergence, to obtain the inlet parameters Ma of the matched internal compression flow field. inlet and Re inlet External compression reference flow field; Step 3: Apply viscosity correction to the obtained internal and external compression flow fields based on the high-precision flow simulation results of CFD; The internal compression and external compression reference flow fields obtained in steps 1 and 2 are viscously corrected to obtain the corrected internal compression axisymmetric configuration, external compression axisymmetric configuration, and the corresponding inviscid flow field of the corrected configuration. Step 4: Generate the waverider forebody; Based on the external compression reference flow field obtained in step 2 and the inviscid external compression reference flow field corrected in step 3, a waverider forebody is designed and obtained. Step 5: Generate an integrated configuration; Based on the internal compression reference flow field obtained in step 1, the inviscid internal compression reference flow field modified in step 3, and the waverider forebody obtained in step 4, an integrated configuration of hypersonic waverider forebody-internal rotating inlet is designed.

2. The integrated design method for a hypersonic waverider forebody-internal rotating inlet according to claim 1, characterized in that, Step 3 includes the following sub-steps: Step 3.1: Extract the wall pressure rise of the internal and external compression reference flow fields obtained in Steps 1 and 2. and subscript Indicates internal compression. Indicates external compression; Step 3.2: Based on the inflow conditions of the internal compression reference flow field respectively and external compression reference flow field inflow conditions Solving the Reynolds-averaged Navier-Stokes equations for both internal and external compression axisymmetric configurations yields the reference flow field for viscous internal compression and the wall pressure rise under this reference flow field. and the viscous external compressibility reference flow field and the wall pressure rise under this reference flow field ; Step 3.3: Judgment and Whether the difference is within the set range, and and Whether the difference is within the set range; if it is within the set range, it is considered convergence and the correction ends; if it is not within the set range, the inner compression wall profile and the outer compression wall profile are corrected in the following two cases, specifically: Case 1: If internal compression Or external compression ,but: (1) Based on the inflow conditions of the internal compression reference flow field respectively and external compression reference flow field inflow conditions Solving the inviscid Euler equations for the inner and outer compression axisymmetric configurations yields the inviscid inner compression reference flow field and the inviscid outer compression reference flow field, respectively. (2) Calculate the boundary layer displacement thickness of the reference flow field ; First, the boundary layer thickness is calculated for the viscous internal compression reference flow field and the viscous external compression reference flow field obtained in step 3.

2. The specific process is as follows: at different x-positions in the viscous internal compression reference flow field and the viscous external compression reference flow field obtained in step 3.2, the flow velocity distribution is intercepted to obtain the flow velocity profile. Based on the obtained flow velocity profile, the slope between two points on the flow velocity profile is calculated using the following formula: When the obtained slope satisfies season Then the boundary layer thickness ; Secondly, based on the boundary layer thicknesses of the obtained viscous internal compression reference flow field and viscous external compression reference flow field, the boundary layer thickness at different x-direction positions is calculated using the following formula. Apply boundary layer displacement thickness New coordinates in the r direction after the position In the formula, the subscript inv represents the inviscid reference flow field calculated in (1) of case 1, and the subscript vis represents the viscous reference flow field calculated in step 3.

2. The axisymmetric boundary layer displacement thickness was then calculated to be: Internal compression displacement thickness: External compression displacement thickness: (3) At different x-positions, the calculated inner compression displacement thickness is applied to the inner compression wall for positive r-axis offset, and the calculated outer compression displacement thickness is applied to the outer compression wall for negative r-axis offset; Case 2: If internal compression Or external compression ,but: At different x-positions, the displacement thickness calculated in the previous iteration that determined whether to enter case 1 will be used. Half of the material is applied to the inner compression wall surface for a negative r-axis offset, and the displacement thickness calculated in the previous iteration that determined whether to enter case 1 is used. Half of it is applied to the outer compression wall surface for positive r-axis offset; Step 3.4: Repeat steps 3.2 and 3.3 until convergence, and finally obtain the modified axisymmetric configuration and the corresponding inviscid flow field of the modified configuration.

3. The integrated design method for a hypersonic waverider forebody-internal rotating inlet according to claim 1, characterized in that, Step 4 includes the following sub-steps: Step 4.1: Design the frontal projection profile FCT on the bottom circle; Step 4.2: Starting from the bottom circle, using the FCT profile obtained in Step 4.1 as the outline, extend along the reverse flow direction to generate the upper surface of the waverider, which intersects with the leading edge shock surface LS designed in Step 2 to obtain the leading edge profile of the waverider. Step 4.3: Using the leading edge profile obtained in Step 4.2 as the outline, start from the flow direction and perform streamline tracing in the inviscid external compression reference flow field after the correction in Step 3 until the bottom circle of the leading edge shock surface LS. Generate the waverider surface, i.e. the lower surface of the waverider, according to the streamline. Combine the upper and lower surfaces of the waverider to obtain the waverider front body.

4. The integrated design method for a hypersonic waverider forebody-internal rotating inlet according to claim 1, characterized in that, Step 5 includes the following sub-steps: Step 5.1: Set the flow rate m to be captured. Within the plane of symmetry, along the leading edge shock surface LS, move the lower lip point of the inner compression incident shock surface IS designed in Step 1 to any position to determine the initial X-direction position of the lower lip. Step 5.2: Rotate the internally compressed incident shock wave surface IS designed in Step 1 along the rotation axis by an angle. To match the flow direction behind the leading edge shock surface LS ; Step 5.3: Scale the inviscid internal compression reference flow field designed in Step 1 according to the set ratio. The internal compression shock surface IS intersects with the leading edge shock surface LS and the waverider surface to obtain the inlet capture inlet FCI. Based on the capture area S, , Calculate the captured flow m; Step 5.4: Determine whether the difference between the calculated capture flow rate and the set required capture flow rate is within the set convergence accuracy. If it is not within the set convergence accuracy, adjust the lower lip point position and scaling ratio, and repeat steps 5.2 to 5.3 until the flow rate requirement is met, and obtain an intake capture inlet that meets the flow rate requirement. Step 5.5: Using the intake capture inlet obtained in step 5.4 as the profile, start along the flow direction and perform streamline tracing in the inviscid internal compression reference flow field after step 3 until the bottom circle, and generate the internal rotating intake profile based on the streamline. Step 5.6: Using the intake capture inlet obtained in Step 5.4 as the contour, start from the flow direction and perform streamline tracing in the inviscid external compression reference flow field after Step 3 until the bottom circle is reached, and generate the outer cover according to the streamline; Step 5.7: Combine the waverider forebody obtained in Step 4, the internal rotating air intake obtained in Step 5.5, and the outer casing obtained in Step 5.6 to form an integrated configuration, and round the leading edge of the configuration according to the set rounding radius to obtain the final hypersonic waverider forebody-internal rotating air intake integrated configuration.

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