Method, device, equipment and medium for determining gas parameters behind oblique shock waves of supersonic vehicles

Abstract

The present application discloses a method, device, equipment and medium for determining the gas parameters behind the oblique shock wave of a supersonic aircraft, and relates to the technical field of fluid calculation research, including: obtaining the current Mach number and the current airflow deflection angle to determine whether the shock wave formed by the supersonic incoming flow on the target component is an oblique shock wave; if it is an oblique shock wave, determining the first set of coefficient values ​​of the preset shock angle equation corresponding to the oblique shock angle formed by the oblique shock wave based on the current Mach number and the current airflow deflection angle, and determining the second set of coefficient values ​​of the change equation corresponding to the preset shock angle equation based on the first set of coefficient values; determining the three angle values ​​corresponding to the oblique shock angle based on the second set of coefficient values ​​and the Cardan formula, determining the target angle value based on the ratio of the post-wave pressure to the wavefront pressure corresponding to the three angle values, and determining the gas parameters behind the oblique shock wave of the supersonic aircraft based on the target angle value. The present application can quickly and accurately determine the gas parameters behind the oblique shock wave of a supersonic aircraft.

Description

Technical Field

[0001] The present invention relates to the technical field of fluid calculation research, and in particular to a method, device, equipment and medium for determining gas parameters behind an oblique shock wave of a supersonic vehicle. Background Art

[0002] Oblique shock waves are a common phenomenon in supersonic airflow. When a supersonic airflow with a Mach number greater than 1 encounters an oblique shock wave with an angle of δ, the airflow direction will be deflected by an angle of δ. Figure 1 As shown in the figure, if the angle δ of the chop is not large, the airflow will generate an oblique shock wave at the leading edge of the chop. The effects of the oblique shock wave include: (1) After the airflow passes through the oblique shock wave, the pressure, temperature and density increase, the airflow velocity decreases, and the airflow direction deflects toward the oblique shock wave surface; (2) The interaction between the oblique shock wave and the boundary layer on the surface of the aircraft may cause boundary layer separation, affecting the lift and maneuverability of the aircraft; (3) The oblique shock wave will cause the wall surface aerodynamic heat to rise. Therefore, the shock wave angle is extremely important for the design of supersonic aircraft components and the detection of component performance after the design is completed.

[0003] For calorimetric perfect gas, given the Mach number M1 upstream of the oblique shock wave and the airflow deflection angle δ, to calculate the oblique shock wave angle β, we can solve a cubic equation for the tangent value tanβ of the oblique shock wave angle β given in the gas dynamics textbook, that is, the preset shock angle equation. The coefficients b1, b2 and b3 of this equation are called the first set of coefficient values.

[0004] ;

[0005] ;

[0006] ;

[0007] .

[0008] Among them, γ is the specific heat ratio. Theoretically, there are three solutions for the shock angle β. The first solution is a weak oblique shock wave solution, the second is a strong oblique shock wave solution, and the third solution is a redundant solution because it will lead to non-physical entropy reduction. Many textbooks on gas dynamics and fluid mechanics point out that the preset shock angle equation cannot be solved directly and needs to be solved by an iterative method. Since the preset shock angle equation has three solutions, the iterative method may miss useful solutions. Moreover, the computational complexity of the iterative method is uncertain. The calculation process of the shock angle is relatively complicated, which affects the efficiency of determining the gas parameters after the oblique shock wave of a supersonic vehicle to a certain extent. Therefore, how to quickly and accurately determine the value of the oblique shock angle needs to be solved. Summary of the invention

[0009] In view of this, the purpose of the present invention is to provide a method, device, equipment and medium for determining the gas parameters behind the oblique shock wave of a supersonic aircraft, which can quickly and accurately determine the gas parameters behind the oblique shock wave of a supersonic aircraft. The specific scheme is as follows:

[0010] In a first aspect, the present application discloses a method for determining gas parameters behind an oblique shock wave of a supersonic vehicle, comprising:

[0011] Acquiring a current Mach number and a current airflow deflection angle of a target component of a supersonic aircraft under a supersonic incoming flow, and judging whether a shock wave formed by the supersonic incoming flow on the target component is an oblique shock wave based on the current Mach number and the current airflow deflection angle;

[0012] If the shock wave formed on the target component is an oblique shock wave, a first set of coefficient values ​​of a preset shock angle equation corresponding to an oblique shock angle formed by the oblique shock wave is determined based on the current Mach number and the current airflow deflection angle, and a second set of coefficient values ​​of a variation equation corresponding to the preset shock angle equation is determined based on the first set of coefficient values; the variation equation is an equation obtained by transforming the preset shock angle equation based on a correlation between the oblique shock angle and the first set of coefficient values;

[0013] The variation equation is solved based on the second set of coefficient values ​​and the Cardan formula to obtain three angle values ​​of the oblique shock wave angle, and a target angle value corresponding to the oblique shock wave angle is determined from the three angle values ​​based on the ratio of the post-wave pressure to the wavefront pressure respectively corresponding to the three angle values, so as to determine the oblique shock wave post-wave gas parameters of the supersonic vehicle based on the target angle value.

[0014] Optionally, judging whether the shock wave formed by the supersonic incoming flow on the target component is an oblique shock wave based on the current Mach number and the current airflow deflection angle includes:

[0015] Inputting the current Mach number, the current airflow deflection angle and the specific heat ratio into a preset deflection angle calculation formula to obtain a maximum airflow deflection angle at which the supersonic incoming flow can generate an oblique shock wave on the target component, and determining whether the current airflow deflection angle is less than the maximum airflow deflection angle;

[0016] If the current airflow deflection angle is smaller than the maximum airflow deflection angle, it is determined that the shock wave formed by the supersonic incoming flow on the target component is an oblique shock wave.

[0017] Optionally, the determining a first set of coefficient values ​​of a preset shock angle equation corresponding to the oblique shock angle formed by the oblique shock wave based on the current Mach number and the current airflow deflection angle, and determining a second set of coefficient values ​​of a change equation corresponding to the preset shock angle equation based on the first set of coefficient values, comprises:

[0018] Inputting the current Mach number, the current airflow deflection angle and the specific heat ratio into the coefficient analytical expression of the preset shock wave angle equation corresponding to the oblique shock wave angle to obtain a first set of coefficient values ​​of the preset shock wave angle equation;

[0019] The preset shock angle equation is transformed according to the correlation between the oblique shock wave angle and the first set of coefficient values ​​to obtain a change equation, and the first set of coefficient values ​​are input into the coefficient analytical expression of the change equation to obtain a second set of coefficient values ​​of the change equation.

[0020] Optionally, determining a target angle value corresponding to the oblique shock wave angle from the three angle values ​​based on a ratio of a post-wave pressure to a front-wave pressure respectively corresponding to the three angle values ​​includes:

[0021] Inputting the current Mach number and specific heat ratio into a preset pressure ratio formula to determine the ratio of the wave rear pressure to the wave front pressure corresponding to the three angle values ​​respectively;

[0022] A target angle value corresponding to the oblique shock wave angle is determined from the three angle values ​​based on the ratio of the post-wave pressure to the front-wave pressure.

[0023] Optionally, determining a target angle value corresponding to the oblique shock wave angle from the three angle values ​​based on the ratio of the post-wave pressure to the front-wave pressure includes:

[0024] The angle value corresponding to the ratio less than the preset threshold value in the ratio is determined as a redundant solution, and the angle value with the smallest value among the three angle values ​​except the redundant solution is determined as the target angle value corresponding to the oblique shock wave angle.

[0025] Optionally, after determining the target angle value corresponding to the oblique shock wave angle from the three angle values ​​based on the ratio of the wave rear pressure to the wave front pressure respectively corresponding to the three angle values, the method further includes:

[0026] The target angle value is tested for angle accuracy based on the airflow parameter table before and after the oblique shock wave, the current Mach number and the current airflow deflection angle.

[0027] Optionally, determining the gas parameters after the oblique shock wave of the supersonic vehicle based on the target angle value includes:

[0028] The target angle value, the current Mach number and the specific heat ratio are input into a preset post-wave gas parameter calculation formula to determine the oblique shock wave post-wave pressure, the oblique shock wave post-wave Mach number and the oblique shock wave post-wave temperature of the supersonic aircraft.

[0029] In a second aspect, the present application discloses a device for determining gas parameters after an oblique shock wave of a supersonic vehicle, comprising:

[0030] a shock wave angle judgment module, used for obtaining a current Mach number and a current airflow deflection angle of a target component of a supersonic aircraft under a supersonic incoming flow, and judging whether a shock wave formed by the supersonic incoming flow on the target component is an oblique shock wave based on the current Mach number and the current airflow deflection angle;

[0031] a coefficient value determination module, for determining, if the shock wave formed on the target component is an oblique shock wave, a first set of coefficient values ​​of a preset shock angle equation corresponding to an oblique shock angle formed by the oblique shock wave based on the current Mach number and the current airflow deflection angle, and determining, based on the first set of coefficient values, a second set of coefficient values ​​of a variation equation corresponding to the preset shock angle equation; the variation equation is an equation obtained by transforming the preset shock angle equation based on a correlation between the oblique shock angle and the first set of coefficient values;

[0032] A post-wave gas parameter determination module is used to solve the change equation based on the second set of coefficient values ​​and the Cardan formula to obtain three angle values ​​of the oblique shock wave angle, and determine the target angle value corresponding to the oblique shock wave angle from the three angle values ​​based on the ratio of the post-wave pressure to the wavefront pressure respectively corresponding to the three angle values, so as to determine the post-wave gas parameter of the oblique shock wave of the supersonic aircraft based on the target angle value.

[0033] In a third aspect, the present application discloses an electronic device, comprising:

[0034] Memory, used to store computer programs;

[0035] A processor is used to execute the computer program to implement the aforementioned method for determining gas parameters behind the oblique shock wave of a supersonic vehicle.

[0036] In a fourth aspect, the present application discloses a computer-readable storage medium for storing a computer program, which, when executed by a processor, implements the aforementioned method for determining gas parameters after an oblique shock wave of a supersonic vehicle.

[0037] It can be seen that in the present application, the current Mach number and the current airflow deflection angle of the target component of the supersonic aircraft under the supersonic incoming flow are obtained, and based on the current Mach number and the current airflow deflection angle, it is determined whether the shock wave formed on the target component by the supersonic incoming flow is an oblique shock wave; if the shock wave formed on the target component is an oblique shock wave, a first group of coefficient values ​​of the preset shock angle equation corresponding to the oblique shock wave angle formed by the oblique shock wave is determined based on the current Mach number and the current airflow deflection angle, and the variable corresponding to the preset shock angle equation is determined based on the first group of coefficient values. The second set of coefficient values ​​of the transformation equation; the transformation equation is an equation obtained by transforming the preset shock angle equation based on the correlation between the oblique shock wave angle and the first set of coefficient values; the transformation equation is solved based on the second set of coefficient values ​​and the Cardan formula to obtain three angle values ​​of the oblique shock wave angle, and the target angle value corresponding to the oblique shock wave angle is determined from the three angle values ​​based on the ratio of the wave rear pressure to the wave front pressure corresponding to the three angle values, so as to determine the oblique shock wave rear gas parameter of the supersonic aircraft based on the target angle value. The present invention uses the general formula solution and coefficient relationship of the cubic equation of one variable to quickly and accurately determine the oblique shock wave rear gas parameter of the supersonic aircraft. On the one hand, three solutions of the oblique shock wave angle can be obtained at one time without missing any solution. On the other hand, the iterative calculation process of calculating the oblique shock wave angle is omitted, and the amount of calculation is reduced to a certain extent, which improves the speed of determining the oblique shock wave rear gas parameter of the supersonic aircraft from the side, thereby improving the efficiency of determining the pressure and heat flow on the surface of the aircraft component. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0039] Figure 1 This is a schematic diagram of the oblique shock wave angle disclosed in this application;

[0040] Figure 2 A flow chart of a method for determining gas parameters behind an oblique shock wave of a supersonic vehicle disclosed in the present application;

[0041] Figure 3 A flow chart of a method for determining gas parameters after an oblique shock wave of a specific supersonic vehicle disclosed in the present application;

[0042] Figure 4 A weak oblique shock angle solution of the shock angle β equation disclosed in this application;

[0043] Figure 5 A strong oblique shock angle solution of the shock angle β equation disclosed in this application;

[0044] Figure 6 This is a schematic diagram of the structure of a device for determining gas parameters after an oblique shock wave of a supersonic aircraft disclosed in the present application;

[0045] Figure 7 This is a structural diagram of an electronic device disclosed in this application. DETAILED DESCRIPTION

[0046] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0047] Oblique shock waves are a common phenomenon in the flow field of supersonic aircraft during flight. Some components of supersonic aircraft are composed of oblique wedges or compression surfaces. For example, the two-dimensional compression inlet of a supersonic fighter is composed of a group of oblique wedges. When a supersonic airflow with a Mach number greater than 1 encounters an oblique wedge or compression surface with an angle of δ, the airflow direction will be deflected by an angle of δ. If the angle δ of the wedge is not large, the airflow will generate an oblique shock wave at the leading edge of the wedge. Usually, the gas parameters of the supersonic incoming flow (for example, Mach number M1, pressure P1, temperature T1, etc.) are known, and the angle δ of the wedge or compression surface is also known. According to the gas parameters and the wedge angle of the supersonic incoming flow, the gas parameters after the oblique shock wave (for example, Mach number M2, pressure P2, temperature T2, etc.) can be calculated using the gas dynamics equation, and then the pressure and heat flow on the surface of the aircraft component can be calculated using engineering methods. Therefore, this application will introduce the calculation process of the gas parameters after the oblique shock wave in detail.

[0048] See also Figure 2 As shown, the embodiment of the present application discloses a method for determining gas parameters after an oblique shock wave of a supersonic vehicle, comprising:

[0049] Step S11: obtaining a current Mach number and a current airflow deflection angle of a target component of a supersonic aircraft under a supersonic incoming flow, and judging whether a shock wave formed by the supersonic incoming flow on the target component is an oblique shock wave based on the current Mach number and the current airflow deflection angle.

[0050] In this embodiment, first Figure 1As shown, the airflow deflection angle δ is determined according to the geometric relationship between the supersonic incoming flow direction and the oblique wedge or compression surface. Wherein, judging whether the shock wave formed by the supersonic incoming flow on the target component is an oblique shock wave based on the current Mach number and the current airflow deflection angle includes: inputting the current Mach number, the current airflow deflection angle and the specific heat ratio into a preset deflection angle calculation formula to obtain the maximum airflow deflection angle at which the supersonic incoming flow can generate an oblique shock wave on the target component, and judging whether the current airflow deflection angle is less than the maximum airflow deflection angle; if the current airflow deflection angle is less than the maximum airflow deflection angle, it is judged that the shock wave formed by the supersonic incoming flow on the target component is an oblique shock wave. Then, the maximum deflection angle δ that can generate an oblique shock wave is calculated using the following formula: max . The formula is as follows:

[0051] ;

[0052] Among them, β max is the maximum deflection angle δ max The maximum oblique shock wave angle is , M1 is the current Mach number; γ is the specific heat ratio. When the incoming flow is pure air, the Mach number M1=2.4, the oblique angle is 16 degrees, the specific heat ratio δ is 1.4, the pressure P1=101325Pa, and the temperature T1=300K. Then, according to the geometric relationship between the supersonic incoming flow direction and the oblique angle, the airflow deflection angle δ is determined to be 16 degrees; the maximum deflection angle δ max is 22.31 degrees. Determine whether it is a detached shock wave or an oblique shock wave. If the airflow deflection angle δ is greater than δ max , there will be a detached shock wave, and there will be no oblique shock wave angle. Otherwise, it is an oblique shock wave. In this embodiment, since 16<22.31. Therefore, it is an oblique shock wave.

[0053] Step S12: If the shock wave formed on the target component is an oblique shock wave, a first set of coefficient values ​​of a preset shock angle equation corresponding to the oblique shock angle formed by the oblique shock wave is determined based on the current Mach number and the current airflow deflection angle, and a second set of coefficient values ​​of a variation equation corresponding to the preset shock angle equation is determined based on the first set of coefficient values; the variation equation is an equation obtained by transforming the preset shock angle equation based on the correlation between the oblique shock angle and the first set of coefficient values.

[0054] In this embodiment, the first set of coefficient values ​​of the preset shock angle equation corresponding to the oblique shock angle formed by the oblique shock wave is determined based on the current Mach number and the current airflow deflection angle, and the second set of coefficient values ​​of the change equation corresponding to the preset shock angle equation is determined based on the first set of coefficient values, including: inputting the current Mach number, the current airflow deflection angle and the specific heat ratio into the coefficient analytical expression of the preset shock angle equation corresponding to the oblique shock angle to obtain the first set of coefficient values ​​of the preset shock angle equation; transforming the preset shock angle equation according to the correlation between the oblique shock angle and the first set of coefficient values ​​to obtain the change equation, and inputting the first set of coefficient values ​​into the coefficient analytical expression of the change equation to obtain the second set of coefficient values ​​of the change equation. That is, firstly, according to the following formula, the first set of coefficient values ​​of the shock angle equation is calculated, including: b1, b2 and b3.

[0055] ;

[0056] ;

[0057] .

[0058] According to the above values, we can get b1=-7.714, b2=3.677, b3=1.621. After calculating the first set of coefficient values, we can calculate the coefficients p and q of the transformation equation according to the first set of coefficient values. The coefficients p and q are called the second set of coefficients. First, let:

[0059] ;

[0060] Then the following default shock angle equation can be used:

[0061] ;

[0062] The transformation equation is as follows:

[0063] ;

[0064] We can further get:

[0065] ;

[0066] ;

[0067] From the above, we can see that p=-16.158, q=-22.925.

[0068] Step S13: Solving the variation equation based on the second set of coefficient values ​​and the Cardan formula to obtain three angle values ​​of the oblique shock wave angle, and determining the target angle value corresponding to the oblique shock wave angle from the three angle values ​​based on the ratio of the post-wave pressure to the wavefront pressure respectively corresponding to the three angle values, so as to determine the oblique shock wave post-gas parameters of the supersonic vehicle based on the target angle value.

[0069] In this embodiment, Figure 3 As shown, first calculate the discriminant ∆:

[0070] ;

[0071] When ∆≥0, because complex roots will be generated, it does not meet the requirements of gas dynamics, so an "error message" is output;

[0072] When ∆<0, the default shock angle equation has 3 different real roots. Since ∆=-24.839<0, there are 3 different real roots.

[0073] In this embodiment, the change equation is solved based on the second set of coefficient values ​​and the Cardan formula to obtain three angle values ​​of the oblique shock wave angle, and the three oblique shock wave angles β1, β2 and β3 are calculated according to the Cardan formula. According to the Cardan formula, the three roots of the change equation are:

[0074] ; (1)

[0075] ; (2)

[0076] ; (3)

[0077] in, ; .

[0078] The relationship between the three roots and the coefficients is:

[0079] ; ; . (4)

[0080] make: ; . (5)

[0081] Then there is ; ; . (6)

[0082] Furthermore, substituting (5) into (1) to (3) yields:

[0083] ; (7)

[0084] ; (8)

[0085] . (9)

[0086] Furthermore, substituting (7) to (9) into (4) yields:

[0087] ; ; . (10)

[0088] Finally, we can get: . (11)

[0089] When ∆<0, then is a complex number. According to equation (5), the expressions in the cube roots of A and B are mutually conjugate complex numbers, so A and B are also complex numbers. Considering that at least one of the three roots of the transformation equation is a real root, assume that x1 is a real root. According to equation (7), the imaginary parts of A and B are opposite. According to equation (11), A and B are conjugate complex numbers. According to equations (8) and (9), x2 and x3 are also real numbers. Moreover, these three real roots are different from each other. Then assume:

[0090] ; (12)

[0091] in:

[0092] ; (13)

[0093] ; (14)

[0094] Note: Since ∆<0, it follows that p<0. Substituting (12) into (5), we obtain:

[0095] ; (15)

[0096] ; (16)

[0097] Substituting equations (15) and (16) into equations (7) to (9), we can obtain:

[0098] ; (17)

[0099] ; (18)

[0100] ; (19)

[0101] Substitute (17) to (19) into In this case, we can get:

[0102] ;

[0103] ;

[0104] .

[0105] Through the above calculations, it can be obtained that β1=82.06, β2=39.35, and β3=-15.41. Furthermore, the method of determining the target angle value corresponding to the oblique shock wave angle from the three angle values ​​based on the ratio of the rear pressure to the wave front pressure corresponding to the three angle values ​​respectively includes: inputting the current Mach number and the specific heat ratio into the preset pressure ratio formula to determine the ratio of the rear pressure to the wave front pressure corresponding to the three angle values ​​respectively; and determining the target angle value corresponding to the oblique shock wave angle from the three angle values ​​based on the ratio of the rear pressure to the wave front pressure. Specifically, the method of determining the target angle value corresponding to the oblique shock wave angle from the three angle values ​​based on the ratio of the rear pressure to the wave front pressure includes: determining the angle value corresponding to the ratio less than the preset threshold value in the ratio as a redundant solution, and determining the angle value with the smallest value among the other angle values ​​in the three angle values ​​except the redundant solution as the target angle value corresponding to the oblique shock wave angle. According to the relationship between the front and rear pressure ratios of the oblique shock wave, the ratios P2 / P1 of the front pressure P1 and the rear pressure P2 of the three oblique shock wave angles are calculated respectively. The preset pressure ratio formula is as follows:

[0106] .

[0107] Among them, P2 / P1 of these three oblique shock wave angles are 6.425, 2.535 and 0.308 respectively. When the pressure ratio P2 / P1 before and after an oblique shock wave angle (without loss of generality, assumed to be β3) is less than 1, this is contrary to the nature of the shock wave and will lead to a non-physical entropy reduction, so this β3 is a redundant solution. Among β1 and β2, the larger one is a strong oblique shock wave solution, and the Mach number after the wave is generally less than 1; the smaller one is a weak oblique shock wave solution, and the Mach number after the shock wave may be greater than 1 or slightly less than 1. After countless experimental observations, it has been determined that any shock wave intensity determined by the airflow deflection angle δ, as long as it is an attached shock wave, is a weak oblique shock wave solution. Therefore, the weak oblique shock angle is:

[0108] .

[0109] That is, eliminate redundant solutions. Figure 4 and Figure 5As shown in the figure, since P2 / P1=0.308<1 of β3, β3 is a redundant solution. Then calculate the final solution - weak oblique shock wave solution. The minimum value between β1 and β2 is β2=39.35. So the oblique shock wave angle is 39.35 degrees.

[0110] Furthermore, after determining the target angle value corresponding to the oblique shock wave angle from the three angle values ​​based on the ratio of the wave rear pressure to the wave front pressure corresponding to the three angle values, it also includes: performing angle accuracy detection on the target angle value based on the oblique shock wave front and rear airflow parameter table, the current Mach number and the current airflow deflection angle. Most aerodynamic textbooks have oblique shock wave front and rear airflow parameter tables, for example: "Gas Dynamics" (Tong Binggang, Kong Xiangyan, Deng Guohua, etc., Gas Dynamics, Beijing: Higher Education Press, May 1990) has oblique shock wave front and rear airflow parameter tables, which have incoming flow parameters: Ma number 1.05~3.9, several airflow deflection angles δ. The corresponding oblique shock wave angles β are given. If the Ma number and δ are in this range in the table, they can be obtained by looking up the table. Alternatively, if the incoming flow Ma number and airflow deflection angle δ are not in the textbook, the flow field can be calculated by numerical calculation of computational fluid dynamics. By analyzing the flow field results, the oblique shock wave angle is obtained and then judged. According to the "Airflow Parameters Table before and after the Oblique Shock Wave", when the Mach number M1=2.4 and δ=16 degrees, the angle of the weak oblique shock wave is 39.35 degrees and the angle of the strong oblique shock wave is 82.06 degrees. This is completely consistent with the calculation results of this application. Therefore, the calculation results of this patent are correct.

[0111] In this embodiment, the determination of the gas parameters after the oblique shock wave of the supersonic aircraft based on the target angle value includes: inputting the target angle value, the current Mach number and the specific heat ratio into the preset post-wave gas parameter calculation formula to determine the post-oblique shock wave pressure, the post-oblique shock wave Mach number and the post-oblique shock wave temperature of the supersonic aircraft. Specifically, in the above formula, subscript 1 represents the airflow parameters before the oblique shock wave, and subscript 2 represents the airflow parameters after the oblique shock wave. According to the following formula, the airflow parameters after the oblique shock wave can be obtained:

[0112] ;

[0113] ;

[0114] .

[0115] At this point, the pressure P2, Mach number M2 and temperature T2 after the oblique shock wave can be obtained. That is, by calculating the airflow parameters after the oblique shock wave: P2 / P1=2.535, T2 / T1=1.335, M2=1.75. Then, P2=256859Pa, T2=400.5K can be obtained. In addition, by further using the airflow parameters after the oblique shock wave, the pressure and heat flow on the surface of the aircraft components can be calculated using engineering methods.

[0116] It can be seen that in this embodiment, the current Mach number and the current airflow deflection angle of the target component of the supersonic aircraft under the supersonic incoming flow are obtained, and based on the current Mach number and the current airflow deflection angle, it is determined whether the shock wave formed on the target component by the supersonic incoming flow is an oblique shock wave; if the shock wave formed on the target component is an oblique shock wave, a first group of coefficient values ​​of a preset shock angle equation corresponding to the oblique shock angle formed by the oblique shock wave is determined based on the current Mach number and the current airflow deflection angle, and a second group of coefficient values ​​of a change equation corresponding to the preset shock angle equation is determined based on the first group of coefficient values; the change equation is an equation obtained by transforming the preset shock angle equation based on the correlation between the oblique shock angle and the first group of coefficient values; the change equation is solved based on the second group of coefficient values ​​and the Cardan formula to obtain three angle values ​​of the oblique shock angle, and a target angle value corresponding to the oblique shock angle is determined from the three angle values ​​based on the ratio of the wave rear pressure to the wave front pressure respectively corresponding to the three angle values, so as to determine the oblique shock wave rear gas parameters of the supersonic aircraft based on the target angle value. The present invention utilizes the universal formula solution and coefficient relationship of the cubic equation to quickly and accurately determine the gas parameters behind the oblique shock wave of a supersonic aircraft. On the one hand, three solutions of the oblique shock wave angle can be obtained at one time without missing any solution. On the other hand, the iterative calculation process of calculating the oblique shock wave angle is omitted, and the amount of calculation is reduced to a certain extent, which indirectly improves the speed of determining the gas parameters behind the oblique shock wave of a supersonic aircraft, thereby improving the efficiency of determining the pressure and heat flow on the surface of the aircraft components.

[0117] refer to Figure 6 The embodiment of the present application also discloses a device for determining gas parameters after an oblique shock wave of a supersonic vehicle, including:

[0118] A shock wave angle judgment module 11 is used to obtain a current Mach number and a current airflow deflection angle of a target component of a supersonic aircraft under a supersonic incoming flow, and judge whether a shock wave formed by the supersonic incoming flow on the target component is an oblique shock wave based on the current Mach number and the current airflow deflection angle;

[0119] a coefficient value determination module 12, for determining, if the shock wave formed on the target component is an oblique shock wave, a first set of coefficient values ​​of a preset shock angle equation corresponding to an oblique shock angle formed by the oblique shock wave based on the current Mach number and the current airflow deflection angle, and determining a second set of coefficient values ​​of a variation equation corresponding to the preset shock angle equation based on the first set of coefficient values; the variation equation is an equation obtained by transforming the preset shock angle equation based on a correlation between the oblique shock angle and the first set of coefficient values;

[0120] The post-wave gas parameter determination module 13 is used to solve the change equation based on the second set of coefficient values ​​and the Cardan formula to obtain three angle values ​​of the oblique shock wave angle, and determine the target angle value corresponding to the oblique shock wave angle from the three angle values ​​based on the ratio of the post-wave pressure to the wavefront pressure respectively corresponding to the three angle values, so as to determine the post-wave gas parameter of the oblique shock wave of the supersonic aircraft based on the target angle value.

[0121] It can be seen that in this embodiment, by solving the coefficient relationship in the analytical formula method of the oblique shock wave angle, that is, the general formula solution of the cubic equation of one variable. On the one hand, three solutions of the oblique shock wave angle can be obtained at one time without missing any solution. The iterative calculation process of calculating the oblique shock wave angle is omitted, and the amount of calculation is reduced to a certain extent, which indirectly improves the speed of determining the gas parameters after the oblique shock wave of the supersonic aircraft, thereby improving the efficiency of determining the pressure and heat flow on the surface of the aircraft components.

[0122] In some specific embodiments, the shock wave angle determination module 11 may specifically include:

[0123] An angle judgment unit is used to input the current Mach number, the current airflow deflection angle and the specific heat ratio into a preset deflection angle calculation formula to obtain a maximum airflow deflection angle at which the supersonic incoming flow can generate an oblique shock wave on the target component, and to judge whether the current airflow deflection angle is less than the maximum airflow deflection angle;

[0124] The shock wave determination unit is used to determine that the shock wave formed by the supersonic incoming flow on the target component is an oblique shock wave if the current airflow deflection angle is less than the maximum airflow deflection angle.

[0125] In some specific embodiments, the coefficient value determination module 12 may specifically include:

[0126] A first set of coefficient determination unit is used to input the current Mach number, the current airflow deflection angle and the specific heat ratio into the coefficient analytical expression of the preset shock angle equation corresponding to the oblique shock angle to obtain a first set of coefficient values ​​of the preset shock angle equation;

[0127] The second set of coefficient determination unit is used to transform the preset shock wave angle equation according to the correlation between the oblique shock wave angle and the first set of coefficient values ​​to obtain a change equation, and input the first set of coefficient values ​​into the coefficient analytical expression of the change equation to obtain a second set of coefficient values ​​of the change equation.

[0128] In some specific embodiments, the post-wave gas parameter determination module 13 may specifically include:

[0129] A pressure ratio determination unit, used for inputting the current Mach number and specific heat ratio into a preset pressure ratio formula to determine the ratio of the wave rear pressure to the wave front pressure corresponding to the three angle values ​​respectively;

[0130] The angle value determination submodule is used to determine the target angle value corresponding to the oblique shock wave angle from the three angle values ​​based on the ratio of the post-wave pressure to the wavefront pressure.

[0131] In some specific embodiments, the angle value determination submodule can be specifically used to determine the angle value corresponding to the ratio of the ratio that is less than a preset threshold as a redundant solution, and determine the angle value with the smallest value among the three angle values ​​except the redundant solution as the target angle value corresponding to the oblique shock wave angle.

[0132] In some specific embodiments, the device for determining gas parameters after the oblique shock wave of a supersonic vehicle may further include:

[0133] The accuracy detection module is used to perform angle accuracy detection on the target angle value based on the airflow parameter table before and after the oblique shock wave, the current Mach number and the current airflow deflection angle.

[0134] In some specific embodiments, the post-wave gas parameter determination module 13 can be specifically used to input the target angle value, the current Mach number and the specific heat ratio into a preset post-wave gas parameter calculation formula to determine the oblique shock wave post-wave pressure, the oblique shock wave post-wave Mach number and the oblique shock wave post-wave temperature of the supersonic aircraft.

[0135] Furthermore, the present application also discloses an electronic device. Figure 7 This is a structural diagram of an electronic device 20 according to an exemplary embodiment. The content in the diagram cannot be regarded as any limitation on the scope of use of the present application.

[0136] Figure 7A schematic diagram of the structure of an electronic device 20 provided in an embodiment of the present application. The electronic device 20 may specifically include: at least one processor 21, at least one memory 22, a power supply 23, a communication interface 24, an input / output interface 25, and a communication bus 26. The memory 22 is used to store a computer program, which is loaded and executed by the processor 21 to implement the relevant steps in the method for calculating the gas parameters after the oblique shock wave of a supersonic aircraft disclosed in any of the aforementioned embodiments. In addition, the electronic device 20 in this embodiment may specifically be an electronic computer.

[0137] In this embodiment, the power supply 23 is used to provide working voltage for each hardware device on the electronic device 20; the communication interface 24 can create a data transmission channel between the electronic device 20 and the external device, and the communication protocol it follows is any communication protocol that can be applied to the technical solution of the present application, and is not specifically limited here; the input and output interface 25 is used to obtain external input data or output data to the outside world, and its specific interface type can be selected according to specific application needs and is not specifically limited here.

[0138] In addition, the memory 22, as a carrier for storing resources, can be a read-only memory, a random access memory, a disk or an optical disk, etc. The resources stored thereon can include an operating system 221, a computer program 222, etc., and the storage method can be temporary storage or permanent storage.

[0139] The operating system 221 is used to manage and control the hardware devices and computer program 222 on the electronic device 20, and can be Windows Server, Netware, Unix, Linux, etc. In addition to the computer program that can be used to complete the method for calculating the gas parameters of the oblique shock wave of a supersonic vehicle executed by the electronic device 20 disclosed in any of the aforementioned embodiments, the computer program 222 can further include computer programs that can be used to complete other specific tasks.

[0140] Furthermore, the present application also discloses a computer-readable storage medium for storing a computer program; wherein, when the computer program is executed by a processor, the aforementioned method for determining the gas parameters of the oblique shock wave of a supersonic vehicle is implemented. The specific steps of the method can be referred to the corresponding contents disclosed in the aforementioned embodiments, and will not be described in detail here.

[0141] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0142] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in the above description according to function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0143] The steps of the method or algorithm described in conjunction with the embodiments disclosed herein may be implemented directly using hardware, a software module executed by a processor, or a combination of the two. The software module may be placed in a random access memory (RAM), a memory, a read-only memory (ROM), an electrically programmable ROM, an electrically erasable programmable ROM, a register, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

[0144] Finally, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0145] The technical solution provided by the present application is introduced in detail above. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea. At the same time, for general technicians in this field, according to the idea of ​​the present application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A method for determining gas parameters behind an oblique shock wave of a supersonic vehicle, characterized in that: include: Acquiring a current Mach number and a current airflow deflection angle of a target component of a supersonic aircraft under a supersonic incoming flow, and judging whether a shock wave formed by the supersonic incoming flow on the target component is an oblique shock wave based on the current Mach number and the current airflow deflection angle; If the shock wave formed on the target component is an oblique shock wave, determining a first set of coefficient values ​​of a preset shock angle equation corresponding to an oblique shock angle formed by the oblique shock wave based on the current Mach number and the current airflow deflection angle, and determining a second set of coefficient values ​​of a variation equation corresponding to the preset shock angle equation based on the first set of coefficient values; The variation equation is an equation obtained by transforming the preset shock angle equation based on the correlation between the oblique shock angle and the first set of coefficient values; Solving the variation equation based on the second set of coefficient values ​​and the Cardan formula to obtain three angle values ​​of the oblique shock wave angle, and determining a target angle value corresponding to the oblique shock wave angle from the three angle values ​​based on the ratio of the wave rear pressure to the wave front pressure respectively corresponding to the three angle values, so as to determine the oblique shock wave rear gas parameter of the supersonic vehicle based on the target angle value; Wherein, the determining the target angle value corresponding to the oblique shock wave angle from the three angle values ​​based on the ratio of the wave rear pressure to the wave front pressure respectively corresponding to the three angle values ​​comprises: inputting the current Mach number and the specific heat ratio into a preset pressure ratio formula to determine the ratio of the wave rear pressure to the wave front pressure respectively corresponding to the three angle values; determining the target angle value corresponding to the oblique shock wave angle from the three angle values ​​based on the ratio of the wave rear pressure to the wave front pressure; The determining the target angle value corresponding to the oblique shock wave angle from the three angle values ​​based on the ratio of the post-wave pressure to the wavefront pressure comprises: determining the angle value corresponding to the ratio less than a preset threshold value among the ratios as a redundant solution, and determining the angle value with the smallest value among the other angle values ​​among the three angle values ​​except the redundant solution as the target angle value corresponding to the oblique shock wave angle; After determining the target angle value corresponding to the oblique shock wave angle from the three angle values ​​based on the ratio of the post-wave pressure to the wave front pressure corresponding to the three angle values ​​respectively, it also includes: performing angle accuracy detection on the target angle value based on the airflow parameter table before and after the oblique shock wave, the current Mach number and the current airflow deflection angle.

2. The method for determining gas parameters behind an oblique shock wave of a supersonic vehicle according to claim 1, characterized in that: The determining, based on the current Mach number and the current airflow deflection angle, whether the shock wave formed by the supersonic incoming flow on the target component is an oblique shock wave comprises: Inputting the current Mach number, the current airflow deflection angle and the specific heat ratio into a preset deflection angle calculation formula to obtain a maximum airflow deflection angle at which the supersonic incoming flow can generate an oblique shock wave on the target component, and determining whether the current airflow deflection angle is less than the maximum airflow deflection angle; If the current airflow deflection angle is smaller than the maximum airflow deflection angle, it is determined that the shock wave formed by the supersonic incoming flow on the target component is an oblique shock wave.

3. The method for determining gas parameters behind an oblique shock wave of a supersonic vehicle according to claim 1, characterized in that: The method of determining a first set of coefficient values ​​of a preset shock angle equation corresponding to an oblique shock wave angle formed by the oblique shock wave based on the current Mach number and the current airflow deflection angle, and determining a second set of coefficient values ​​of a change equation corresponding to the preset shock angle equation based on the first set of coefficient values, comprises: Inputting the current Mach number, the current airflow deflection angle and the specific heat ratio into the coefficient analytical expression of the preset shock wave angle equation corresponding to the oblique shock wave angle to obtain a first set of coefficient values ​​of the preset shock wave angle equation; The preset shock angle equation is transformed according to the correlation between the oblique shock wave angle and the first set of coefficient values ​​to obtain a change equation, and the first set of coefficient values ​​are input into the coefficient analytical expression of the change equation to obtain a second set of coefficient values ​​of the change equation.

4. The method for determining gas parameters behind an oblique shock wave of a supersonic vehicle according to any one of claims 1 to 3, characterized in that: The determining of the gas parameters after the oblique shock wave of the supersonic vehicle based on the target angle value comprises: The target angle value, the current Mach number and the specific heat ratio are input into a preset post-wave gas parameter calculation formula to determine the oblique shock wave post-wave pressure, the oblique shock wave post-wave Mach number and the oblique shock wave post-wave temperature of the supersonic aircraft.

5. A device for determining gas parameters behind an oblique shock wave of a supersonic vehicle, characterized in that: include: a shock wave angle judgment module, used for obtaining a current Mach number and a current airflow deflection angle of a target component of a supersonic aircraft under a supersonic incoming flow, and judging whether a shock wave formed by the supersonic incoming flow on the target component is an oblique shock wave based on the current Mach number and the current airflow deflection angle; a coefficient value determination module, configured to determine, if the shock wave formed on the target component is an oblique shock wave, a first set of coefficient values ​​of a preset shock angle equation corresponding to an oblique shock angle formed by the oblique shock wave based on the current Mach number and the current airflow deflection angle, and determine a second set of coefficient values ​​of a variation equation corresponding to the preset shock angle equation based on the first set of coefficient values; The variation equation is an equation obtained by transforming the preset shock angle equation based on the correlation between the oblique shock angle and the first set of coefficient values; a post-wave gas parameter determination module, configured to solve the variation equation based on the second set of coefficient values ​​and the Cardan formula to obtain three angle values ​​of the oblique shock wave angle, and determine a target angle value corresponding to the oblique shock wave angle from the three angle values ​​based on the ratio of the post-wave pressure to the wavefront pressure respectively corresponding to the three angle values, so as to determine the post-wave gas parameter of the oblique shock wave of the supersonic vehicle based on the target angle value; Wherein, the determining the target angle value corresponding to the oblique shock wave angle from the three angle values ​​based on the ratio of the wave rear pressure to the wave front pressure respectively corresponding to the three angle values ​​comprises: inputting the current Mach number and the specific heat ratio into a preset pressure ratio formula to determine the ratio of the wave rear pressure to the wave front pressure respectively corresponding to the three angle values; determining the target angle value corresponding to the oblique shock wave angle from the three angle values ​​based on the ratio of the wave rear pressure to the wave front pressure; The determining the target angle value corresponding to the oblique shock wave angle from the three angle values ​​based on the ratio of the post-wave pressure to the wavefront pressure comprises: determining the angle value corresponding to the ratio less than a preset threshold value among the ratios as a redundant solution, and determining the angle value with the smallest value among the other angle values ​​among the three angle values ​​except the redundant solution as the target angle value corresponding to the oblique shock wave angle; After determining the target angle value corresponding to the oblique shock wave angle from the three angle values ​​based on the ratio of the post-wave pressure to the wave front pressure corresponding to the three angle values ​​respectively, it also includes: performing angle accuracy detection on the target angle value based on the airflow parameter table before and after the oblique shock wave, the current Mach number and the current airflow deflection angle.

6. An electronic device, characterized in that: include: Memory, used to store computer programs; A processor, configured to execute the computer program to implement the method for determining gas parameters after an oblique shock wave of a supersonic vehicle as claimed in any one of claims 1 to 4.

7. A computer-readable storage medium, characterized in that: Used to store a computer program, which, when executed by a processor, implements the method for determining gas parameters after an oblique shock wave of a supersonic aircraft as claimed in any one of claims 1 to 4.

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