Verification method for simulation model of radiation characteristics of ball-nose cone target at high mach number reentry

Abstract

The present application relates to the technical field of aircraft reentry characteristic model verification, in particular to a kind of ball nose cone target high Mach number reentry radiation characteristic simulation model verification method, comprising: the head shock detachment distance of the ball nose cone target is calculated;Using iterative method to solve the final value of incoming flow parameter, wherein, incoming flow parameter includes incoming flow density and incoming flow Mach number;The head point heat flow of the ball nose cone target is calculated;Error analysis is carried out to the head point heat flow of the ball nose cone target calculated, to modify the final value of incoming flow parameter;The final value of the modified incoming flow parameter is input into the preset ball nose cone high Mach reentry radiation characteristic simulation model, and the reentry radiation characteristic data of the ball nose cone target is solved;Ball nose cone target high Mach number reentry radiation characteristic simulation model is verified.The verification method provided by the present application can reduce the influence of incoming flow parameter error on simulation model verification, improve the accuracy of model verification.

Description

Technical Field

[0001] This invention relates to the field of aircraft reentry characteristic model verification technology, and in particular to a verification method for a simulation model of the high Mach number reentry radiation characteristics of a spherical cone target. Background Technology

[0002] The high-Mach reentry process of a ball-nose cone target exerts strong compression and friction on the surrounding air, forming a high-temperature shock layer around the head and generating strong radiation signals; therefore, the study of the characteristics of the reentry process of a ball-nose cone target is of great significance.

[0003] In existing research on the characteristics of spherical cone targets, simulation algorithms are generally used to obtain characteristic data. In order to improve the accuracy of simulation calculations, the simulation model is usually verified and analyzed based on wind tunnel equivalent simulation experiments. The primary condition for verifying the simulation model is to ensure the accuracy of the incoming flow parameters. However, it is difficult to obtain the incoming flow parameters without affecting the experimental environment during wind tunnel experiments.

[0004] Therefore, there is an urgent need to provide a verification method for simulation models that can reduce errors in incoming flow parameters. Summary of the Invention

[0005] This invention provides a verification method for a simulation model of the reentry radiation characteristics of a spherical cone target at high Mach numbers. This verification method improves the accuracy of simulation calculations by correcting the incoming flow parameters, and can reduce the impact of incoming flow parameter errors on the accuracy of model verification.

[0006] To achieve the above objectives, this invention provides a method for verifying a simulation model of the reentry radiation characteristics of a spherical cone target at high Mach numbers, comprising:

[0007] S1. Calculate the head shock wave separation distance of the spherical cone target based on the schlieren map of the spherical cone target obtained from the high Mach number reentry equivalent simulation experiment.

[0008] S2. Based on the preset first empirical formula and the preset initial values ​​of the incoming flow parameters, the final values ​​of the incoming flow parameters are solved by iterative method; wherein, the first empirical formula is the relationship between the head shock wave detachment distance and the incoming flow parameters, and the incoming flow parameters include the incoming flow density and the incoming flow Mach number;

[0009] S3. Input the final values ​​of the incoming flow parameters obtained from the solution into the preset second empirical formula to calculate the head stagnation heat flux of the spherical cone target; wherein, the second empirical formula is the relationship between the head stagnation heat flux and the incoming flow parameters;

[0010] S4. Based on the head stagnation heat flux of the spherical cone target measured by the high Mach number reentry equivalent simulation experiment, an error analysis is performed on the calculated head stagnation heat flux of the spherical cone target to correct the final value of the incoming flow parameters.

[0011] S5. Based on the final values ​​of the corrected incoming flow parameters and the preset simulation model of the high Mach reentry radiation characteristics of the spherical cone, solve for the reentry radiation characteristic data of the spherical cone target; among which, the radiation characteristic data includes surface characteristic data and external flow field characteristic data;

[0012] S6. Compare and analyze the reentry radiation characteristic data obtained by the solution with the reentry radiation characteristic data of the spherical cone target measured by the high Mach number reentry equivalent simulation experiment to verify the simulation model of the high Mach number reentry radiation characteristic of the spherical cone target.

[0013] In one possible design, the first empirical formula is:

[0014]

[0015] Where Δ is the head shock wave detachment distance (mm), R is the head radius (m), and ρ ∞ Incoming flow density (kg / m³) 3 Ma is the Mach number of the incoming flow.

[0016] In one possible design, the second empirical formula is:

[0017]

[0018] Where q is the head stagnation heat flux (W / m) 2 R is the radius of the sphere head (m), V * ρ * These represent the reference velocity and reference density, respectively; c is the local speed of sound; Ma is the incoming Mach number; and ρ is the reference density. ∞ The incoming flow density.

[0019] In one possible design, correcting the final value of the incoming flow parameters includes: determining whether the calculated head stagnation heat flux of the spherical cone target, measured based on the high Mach number reentry equivalent simulation experiment, is within a preset error range; if the calculated head stagnation heat flux is within the preset error range, the final value of the input incoming flow parameters is output to obtain the corrected final value of the incoming flow parameters, and then proceeding to step S5; otherwise, step S2 is repeated until the calculated head stagnation heat flux falls within the preset error range or the error reaches its minimum value.

[0020] In one possible design, the reentry radiation characteristics data are solved using the following formula:

[0021]

[0022] Among them, ξ, ζ is a general coordinate system, t is time, Q is a conserved variable, and F is a constant. c G c Hc F represents the convection flux in the three directions of the coordinate system. v G v H v Let ω represent the viscous flux in the three directions of the coordinate system, Re be the Reynolds number, and Ma be the Mach number.

[0023] In one possible design, the expression for the conserved variable is:

[0024]

[0025] The expression for the source term is:

[0026] Where, ρ s ρ and ρ are the densities of gas component s and the gas mixture, respectively; u, v, w are the velocity components in the three directions, respectively; E and E' are the velocity components in the three directions, respectively. ve These are energy per unit mass and vibrational-electron energy, respectively. This represents the mass production rate of component s. Let J be the vibration-electronic energy term, and J be the Jacobian matrix used for coordinate transformation.

[0027] In one possible design, the surface characteristic data includes at least the surface temperature distribution and the surface heat flux distribution; the external flow field characteristic data includes at least the external flow field temperature distribution.

[0028] Compared with the prior art, the present invention has at least the following beneficial effects:

[0029] This invention uses measured data from a high Mach number re-entry equivalent simulation experiment of a spherical cone target in a wind tunnel to correct the incoming flow parameters in the simulation model of the high Mach number re-entry radiation characteristics of the spherical cone target. This reduces the error between the corrected incoming flow parameters and the actual incoming flow parameters, improves the accuracy of the simulation calculation, and makes the simulation results closer to the results measured in the high Mach number re-entry equivalent simulation experiment, thus ensuring the accuracy of the simulation model verification. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a flowchart illustrating the verification method for the simulation model of the high Mach number reentry radiation characteristics of the spherical cone target of the present invention.

[0032] Figure 2This is a schlieren image of a spherical cone target obtained from a high Mach number reentry equivalent simulation experiment of this invention. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0034] like Figure 1 As shown, this invention provides a method for verifying a simulation model of the reentry radiation characteristics of a spherical cone target at high Mach numbers, comprising:

[0035] S1. Calculate the head shock wave separation distance of the spherical cone target based on the schlieren map of the spherical cone target obtained from the high Mach number reentry equivalent simulation experiment.

[0036] S2. Based on the preset first empirical formula and the preset initial values ​​of the incoming flow parameters, the final values ​​of the incoming flow parameters are solved by iterative method; wherein, the first empirical formula is the relationship between the head shock wave detachment distance and the incoming flow parameters, and the incoming flow parameters include the incoming flow density and the incoming flow Mach number;

[0037] S3. Input the final values ​​of the incoming flow parameters obtained from the solution into the preset second empirical formula to calculate the head stagnation heat flux of the spherical cone target; wherein, the second empirical formula is the relationship between the head stagnation heat flux and the incoming flow parameters;

[0038] S4. Based on the head stagnation heat flux of the spherical cone target measured by the high Mach number reentry equivalent simulation experiment, an error analysis is performed on the calculated head stagnation heat flux of the spherical cone target to correct the final value of the incoming flow parameters.

[0039] S5. Based on the final values ​​of the corrected incoming flow parameters and the preset simulation model of the high Mach reentry radiation characteristics of the spherical cone, solve for the reentry radiation characteristic data of the spherical cone target; among which, the radiation characteristic data includes surface characteristic data and external flow field characteristic data;

[0040] S6. Compare and analyze the reentry radiation characteristic data obtained by the solution with the reentry radiation characteristic data of the spherical cone target measured by the high Mach number reentry equivalent simulation experiment to verify the simulation model of the high Mach number reentry radiation characteristic of the spherical cone target.

[0041] This invention uses measured data from a high Mach number reentry equivalent simulation experiment of a spherical nose cone target conducted in a wind tunnel to correct the incoming flow parameters in the simulation model of the high Mach number reentry radiation characteristics of the spherical nose cone target. This reduces the error between the corrected incoming flow parameters and the actual incoming flow parameters, improves the accuracy of the simulation calculation, and makes the simulation results closer to the results measured in the high Mach number reentry equivalent simulation experiment, ensuring the accuracy of the simulation model verification. It should be noted that the aforementioned measured data includes at least the schlieren image of the spherical nose cone target, the heat flux at the nose stagnation point, and reentry radiation characteristic data, wherein the reentry radiation characteristic data includes surface characteristic data and external flow field characteristic data.

[0042] In some specific implementations, firstly, based on the schlieren map obtained from the equivalent simulation experiment of reentry at high Mach number of the spherical cone target (e.g., Figure 2 This paper investigates the relationship between the head radius and head separation distance of a spherical cone target. Based on the actual radius of the target, a comparative measurement method is used to calculate the head shock wave separation distance. Then, using a preset initial value of the incoming flow parameters and a first empirical formula describing the relationship between the head shock wave separation distance and the incoming flow parameters, an iterative method is employed to solve for the final value of the incoming flow parameters. Further, the final value of the solved incoming flow parameters is input into a preset second empirical formula describing the relationship between the head stagnation heat flux and the incoming flow parameters to calculate the head stagnation heat flux of the spherical cone target. This heat flux is then compared with the head shock wave separation distance measured in a high Mach number reentry equivalent simulation experiment. For the head stagnation heat flux, an error analysis is performed on the calculated head stagnation heat flux of the spherical cone target. If the calculated head stagnation heat flux of the spherical cone target is within the preset error range, the final value of the input inflow parameters is output to obtain the corrected final value of the inflow parameters. Finally, the corrected final value of the inflow parameters is input into the simulation model of the high Mach number reentry radiation characteristics of the spherical cone target to obtain the reentry radiation characteristic data. The data is then compared and analyzed with the reentry radiation characteristic data of the spherical cone target measured based on the equivalent simulation experiment of high Mach number reentry of the spherical cone target, so as to complete the verification of the simulation model of the high Mach number reentry radiation characteristics of the spherical cone target.

[0043] The preset error of this invention is used to determine whether the error between the calculated head stagnation heat flux of the spherical cone target and the head stagnation heat flux of the spherical cone target measured by the high Mach number reentry equivalent simulation experiment is within an acceptable range, and to correct the incoming flow parameters so as to ensure that the final value of the corrected incoming flow parameters is closer to the actual incoming flow parameters, thereby improving the accuracy of the reverse model verification.

[0044] In some implementations, the first empirical formula is:

[0045]

[0046] Where Δ is the head shock wave detachment distance (mm), R is the head radius (m), and ρ ∞ Incoming flow density (kg / m³) 3 Ma is the Mach number of the incoming flow.

[0047] The first empirical formula of the present invention is a first empirical formula that can describe the relationship between the head shock wave detachment distance and the incoming flow parameters; based on the calculated head shock wave detachment distance, the initial values ​​of the preset incoming flow parameters, and the first empirical formula, the final values ​​of the incoming flow parameters (incoming flow density and incoming flow Mach number) that conform to the calculated head shock wave detachment distance can be obtained by using an iterative method.

[0048] In some implementations, the second empirical formula is:

[0049]

[0050] Where q is the head stagnation heat flux (W / m) 2 R is the radius of the sphere head (m), V * ρ * These are the reference velocity and reference density, typically taken as V. * =7900m / s, ρ * =1.2263kg / m 3 c is the local speed of sound, Ma is the Mach number of the incoming flow, and ρ ∞ The incoming flow density.

[0051] It should be noted that the second empirical formula is obtained by simplification based on equation (3);

[0052]

[0053] Among them, U ∞ Let the incoming flow velocity be the velocity, and the relationship between the incoming flow velocity and the incoming flow Mach number satisfy equation (4):

[0054] U ∞ =cMa(4); where c is the local speed of sound and Ma is the Mach number of the incoming flow; the local speed of sound is related to the properties of the gas and its state, and is a specific value for a specific gas under specific conditions.

[0055] Substituting equation (4) into equation (3) yields the second empirical formula. The second empirical formula of this invention is a second empirical formula that can describe the relationship between the head stagnation heat flux and the incoming flow parameters. By inputting the final value of the calculated incoming flow parameters (incoming flow density and incoming flow Mach number) into the second empirical formula, the head stagnation heat flux of the spherical cone target can be obtained. This can be used to compare and analyze the head stagnation heat flux of the spherical cone target measured by the high Mach number reentry equivalent simulation experiment, so as to correct the final value of the input incoming flow parameters.

[0056] In some implementations, correcting the final value of the incoming flow parameters includes: determining whether the calculated head stagnation heat flux of the spherical cone target, measured based on the high Mach number reentry equivalent simulation experiment, is within a preset error range; if the calculated head stagnation heat flux is within the preset error range, the final value of the input incoming flow parameters is output to obtain the corrected final value of the incoming flow parameters, and then proceeding to step S5; otherwise, step S2 is repeated until the calculated head stagnation heat flux falls within the preset error range or the error reaches its minimum value.

[0057] This invention compares and analyzes the head stagnation heat flux calculated using the final value of the incoming flow parameters with the head stagnation heat flux of a spherical cone target measured in a high Mach number reentry equivalent simulation experiment to determine whether the calculated head stagnation heat flux is within a preset error range. If the calculated head stagnation heat flux is within the preset error range, it is considered that the final value of the input incoming flow parameters is close to the true value and can be used for simulation model verification. The final value of the input incoming flow parameters is then output as the corrected final value of the incoming flow parameters. If the calculated head stagnation heat flux is not within the preset error range, there are two scenarios: one is that the steps of repeatedly calculating and correcting the incoming flow parameters are repeated, and the final calculated head stagnation heat flux is within the preset error range; the other is that after repeatedly calculating and correcting the incoming flow parameters, the final calculated head stagnation heat flux consistently fails to fall within the preset error range and eventually reaches a minimum value. In this case, the final value of the input incoming flow parameters is also considered to meet the requirements and can be used for simulation model verification.

[0058] In some implementations, the reentry radiation characteristics data are solved using the following formula:

[0059]

[0060] Among them, ξ, ζ is a general coordinate system, t is time, Q is a conserved variable, and F is a constant. c G c H c F represents the convection flux in the three directions of the coordinate system. v G v H v Let ω represent the viscous flux in the three directions of the coordinate system, Re be the Reynolds number, and Ma be the Mach number.

[0061] In some implementations, the expression for the conserved variable is:

[0062]

[0063] The expression for the source term is:

[0064] Where, ρ s ρ and ρ are the densities of gas component s and the gas mixture, respectively; u, v, w are the velocity components in the three directions, respectively; E and E' are the velocity components in the three directions, respectively. ve These are energy per unit mass and vibrational-electron energy, respectively. This represents the mass production rate of component s. Let J be the vibration-electronic energy term, and J be the Jacobian matrix used for coordinate transformation.

[0065] This invention solves the reentry radiation characteristic data based on the reentry radiation characteristic data solution formula (5) in the simulation model of the reentry radiation characteristic of the high Mach number of the spherical cone target. Based on the dual temperature model in the simulation model of the reentry radiation characteristic of the high Mach number of the spherical cone target, the expression of the conserved variable in formula (5) is formula (6), and the expression of the source term is formula (7), so as to simplify the reentry radiation characteristic data solution formula.

[0066] In some implementation designs, surface characteristic data include at least surface temperature distribution and surface heat flux distribution; external flow field characteristic data includes at least external flow field temperature distribution.

[0067] This invention verifies the simulation model of the high Mach number reentry radiation characteristics of a spherical cone target by comparing the surface characteristic data and external flow field characteristic data obtained from the simulation model of the high Mach number reentry radiation characteristics of the spherical cone target with the surface characteristic data and external flow field characteristic data measured by the equivalent simulation experiment of high Mach number reentry.

[0068] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for calibrating a simulation model of radiation characteristics of a ball-cone target at high Mach number reentry, characterized in that, include: S1. Calculate the head shock wave separation distance of the spherical cone target based on the schlieren map of the spherical cone target obtained from the high Mach number reentry equivalent simulation experiment; S2. Based on the preset first empirical formula and the preset initial values ​​of the incoming flow parameters, the final values ​​of the incoming flow parameters are solved by an iterative method; wherein, the first empirical formula is the relationship between the head shock wave detachment distance and the incoming flow parameters, and the incoming flow parameters include the incoming flow density and the incoming flow Mach number; S3. Input the final value of the obtained incoming flow parameters into the preset second empirical formula to calculate the head stagnation heat flux of the spherical cone target; wherein, the second empirical formula is the relationship between the head stagnation heat flux and the incoming flow parameters; S4. Based on the heat flux at the head stagnation point of the spherical cone target measured by the high Mach number reentry equivalent simulation experiment, an error analysis is performed on the calculated heat flux at the head stagnation point of the spherical cone target to correct the final value of the incoming flow parameter. S5. Input the final value of the corrected incoming flow parameters into the preset high Mach reentry radiation characteristic simulation model of the spherical cone to solve the reentry radiation characteristic data of the spherical cone target; wherein, the reentry radiation characteristic data includes surface characteristic data and external flow field characteristic data; S6. Compare and analyze the obtained reentry radiation characteristic data with the reentry radiation characteristic data of the spherical cone target measured by the high Mach number reentry equivalent simulation experiment to verify the simulation model of the high Mach number reentry radiation characteristic of the spherical cone target.

2. The method of claim 1, wherein, The first empirical formula is: where Δ is the head shock detachment distance, R is the radius of the nose, p ∞ is the free stream density and Ma is the free stream Mach number.

3. The method of claim 1, wherein, The second empirical formula is: Where q is the head stagnation heat flux (W / m) 2 R is the radius of the sphere head (m), V * ρ * These represent the reference velocity and reference density, respectively; c is the local speed of sound; Ma is the incoming Mach number; and ρ is the reference density. ∞ The incoming flow density.

4. The method of claim 1, wherein, Correct the final values ​​of the incoming flow parameters, including: Based on the head stagnation heat flux of the spherical cone target measured by the high Mach number reentry equivalent simulation experiment, it is determined whether the calculated head stagnation heat flux is within the preset error range. If the calculated heat flux at the head stagnation point is within the preset error range, the final value of the input incoming flow parameter is output to obtain the corrected final value of the incoming flow parameter, and then proceed to step S5. Otherwise, repeat step S2 until the calculated head stagnation point heat flux falls within the preset error range or the error reaches its minimum value.

5. The method of claim 1, wherein, The reentry radiation characteristics data are obtained by solving the following formula: Among them, ξ, ζ is a general coordinate system, t is time, Q is a conserved variable, and F is a constant. c G c H c F represents the convection flux in the three directions of the coordinate system. v G v H v Let ω represent the viscous flux in the three directions of the coordinate system, Re be the Reynolds number, and Ma be the Mach number.

6. The verification method according to claim 5, characterized in that, The expression of the conserved variable is: The expression of the source term is: Where, ρ s ρ and ρ are the densities of gas component s and the gas mixture, respectively; u, v, w are the velocity components in the three directions, respectively; E and E' are the velocity components in the three directions, respectively. ve These are energy per unit mass and vibrational-electron energy, respectively. This represents the mass production rate of component s. Let J be the vibration-electronic energy term, and J be the Jacobian matrix used for coordinate transformation.

7. The verification method according to claim 1, characterized in that, The surface characteristic data includes at least the surface temperature distribution and the surface heat flux distribution; the external flow field data includes at least the external flow field temperature distribution.

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