A method for designing a custom interface for a collision integral transport model

Abstract

This invention discloses a method for designing a custom interface for a collision integral transport model, belonging to the field of numerical simulation technology for high-temperature, high-speed thermochemical nonequilibrium flow. The method includes the following steps: constructing a collision integral model UDF parameter file adaptable to calculations involving arbitrary component combinations; constructing a model parameter reading and parsing interface based on the UDF parameter file; constructing a mapping function interface; modifying the UDF parameter file and its associated collision integral transport model and parameters according to calculation needs; and obtaining the thermochemical nonequilibrium steady-state flow field and parameter distribution through coupling with the flow field solver. The custom UDF parameter file established by this invention can adapt to the parameter setting and efficient integrated application requirements of collision integral models under various complex gas environments, and has advantages such as strong readability, extensibility, and flexibility, meeting the physical modeling needs of thermodynamic transport coefficients under arbitrary component combinations.

Description

Technical Field

[0001] This invention belongs to the field of numerical simulation technology of high-temperature and high-speed thermochemical non-equilibrium flow, and specifically relates to a custom interface design method for a collision integral transport model. Background Technology

[0002] In numerical simulations of high-temperature, high-speed thermochemical nonequilibrium flows, high-temperature gas transport models are crucial for predicting the accuracy of aerodynamic characteristics such as aerodynamic forces and aerothermal properties of aircraft, significantly impacting the integrated design of high-speed aircraft systems for aerodynamic control, thermal protection, and communication. Currently, high-temperature gas transport models can be categorized into two types: approximation methods and collision integral methods. The former primarily uses empirical or mathematical fitting formulas to approximate the viscosity coefficient, mass diffusion coefficient, and thermal conductivity coefficient of high-temperature gases. Due to its relatively simple formulas, it is widely used in computational fluid dynamics (CFD). The latter is more computationally complex but has rigorous physical support, resulting in higher accuracy. Compared to approximation methods, collision integral methods offer a unified representation, with the calculation of viscosity coefficient, mass diffusion coefficient, and thermal conductivity coefficient all relying on diffusion-collision integrals. and viscous collision integral Two key parameters. Among them, and This represents the collision pairs of components in a gas mixture.

[0003] Component collision pairs The diffusion and viscous collision integrals are typically calculated using fitting polynomials. For inelastic (Coulomb) collisions, the main methods for calculating collision integrals include the LAURA fitting formula, DPLR fitting formula, and US3D fitting formula; for elastic (Coulomb) collisions, methods include the Wright fitting formula and Gupta fitting formula. Therefore, when developing the program, it is necessary to consider the collision pairs of each component. The calculation parameters are stored and preprocessed. Currently, the commonly used simulation conditions are mainly atmospheric conditions such as air and Martian atmosphere, involving components such as N, O, C, and , NO, CO Therefore, the component collision pairs in the program code are mainly equal. The parameters for fitting calculations are well-defined and fixed, and are typically embedded and stored using two-dimensional or three-dimensional arrays.

[0004] However, with the increasing complexity of gas environments in engineering applications, the gas components to be simulated have become more diverse and abundant. Existing collision integral transport model databases can no longer meet the needs of engineering calculations, and data integration using code embedding methods cannot adapt to diverse calculation needs. This increases the difficulty of model parameter expansion and integration, as well as the cost of code writing, maintenance, and management. There is an urgent need to develop a data storage structure and reading interface that is universal and flexible and convenient for expansion and integration. Summary of the Invention

[0005] The purpose of this invention is to address the aforementioned problems by providing a custom interface design method for collision integral transport models. This method aims to improve the existing collision integral transport model databases, which cannot adapt to the computational needs of diverse gas component combinations, and to address the issues of difficulty in expanding and integrating simulation parameters, as well as high costs in code writing, maintenance, and management.

[0006] The technical solution adopted in this invention is as follows: a method for designing a custom interface for a collision integral transport model, the method specifically including the following steps:

[0007] Step S100: Construct a UDF parameter file based on the collision integral transport model. The components in the UDF parameter file can be arbitrarily combined.

[0008] Step S200: Based on the UDF parameter file of the collision integral transport model, construct a parameter reading and parsing interface for the analytical collision integral model;

[0009] Step S300: Construct a mapping function interface from the collision integral transport model obtained from the UDF parameter file to the collision integral transport model required for actual flow simulation;

[0010] Step S400: Modify the UDF parameter file and its associated collision integral transport model and parameters according to the calculation needs, and obtain the thermochemical non-equilibrium steady-state flow field and parameter distribution by coupling with the flow field solver.

[0011] Furthermore, step S100 specifically includes:

[0012] Based on various complex gas models, common features of the calculation parameters of the collision integral transport model are extracted, and a UDF parameter file is established.

[0013] The UDF parameter file includes I / O control variables, gas mixture composition, and component collision pairs. The three types of information elements are: the parameter set for fitting calculation, and the parameter set.

[0014] Furthermore, step S200 specifically includes:

[0015] Based on the UDF parameter file established in step S100, a storage data structure for calculating parameters of the collision integral model is constructed, and corresponding I / O member functions are established to uniformly design and manage the I / O parsing interface.

[0016] Furthermore, step S300 specifically includes:

[0017] A mapping function interface is constructed from the collision integral transport model obtained from the UDF parameter file to the collision integral transport model required for actual flow simulation. Based on the composition and sorting of the mixed gas components provided by the master control parameter file, the optimized and recombined collision integral transport model parameters are obtained through the mapping function interface, which are used to perform thermochemical nonequilibrium flow iterative solution for the high-temperature nonequilibrium CFD solver.

[0018] Furthermore, step S400 specifically includes:

[0019] The modified UDF parameter file and its associated collision integral transport model and parameters are applied to the numerical iteration process of the high-temperature nonequilibrium CFD solver to update the thermodynamic transport coefficients of the mixed gas components until the convergence condition is met, thus obtaining the final required thermochemical nonequilibrium steady-state flow field and parameter distribution.

[0020] Furthermore, five parameters have been added to the I / O control variable elements, and these five new parameters are placed in the first five lines of the UDF parameter file for memory pre-allocation and parameter reading control.

[0021] The five parameters are: species_num, pair_num, collision_mode, diff_fit_num, and vis_fit_num.

[0022] Furthermore, regarding the component collision pairs in the UDF parameter file The component collision pair and its fitting calculation parameter set section contain two rows of data information, namely the component collision pair. A detailed list of component names and its set of fitting calculation parameters.

[0023] Furthermore, the UDF parameter file allows for component collision pairs Data reuse, subsequent collision pairs of the same components Data replaces the first-appearing component collision pair Data; and component collision pairs Collision pairs with components They belong to the same group of collisions.

[0024] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0025] 1. The collision integral transport model custom interface design method provided by this invention adopts a standardized and flexible custom UDF parameter file and its parsing interface design, which solves the programming redundancy and low reusability problems caused by traditional embedded module coding and data integration extension methods, greatly reduces the difficulty of parameter model extension and integration, and meets the needs of "lightweight" code writing and maintenance management of the calculation module.

[0026] 2. The UDF custom parameter file proposed and established in this invention can adapt to the parameter setting and efficient integration application requirements of collision integral models under various complex gas environments. It has advantages such as strong readability, extensibility, and flexibility of use. It can meet the extensive needs of physical modeling of thermodynamic transport coefficients under arbitrary component combination calculation conditions and their impact on the aerodynamic and thermal environment of high-speed aircraft.

[0027] 3. The custom interface design method for the collision integral transport model proposed and established in this invention is applicable to a variety of complex gas models, including Earth's atmosphere, Martian atmosphere, high-temperature gas, and ablation ejector gas, and can meet the application needs of thermochemical nonequilibrium flow simulation and related aerodynamic characteristic calculation and analysis in complex gas environments. Attached Figure Description

[0028] Figure 1 This is a flowchart of the method of the present invention;

[0029] Figure 2 This is a schematic diagram of the input function for reading the UDF parameter file of the collision integral model of the present invention;

[0030] Figure 3 A schematic diagram of the interface design for optimizing the recombination mapping function for the collision integral model;

[0031] Figure 4 Comparison of wall pressure distribution calculated based on the HEG shock tunnel cylindrical model in Example 1;

[0032] Figure 5 This is a comparison diagram of the wall heat flux distribution calculated based on the HEG shock tunnel cylindrical model in Example 2. Detailed Implementation

[0033] The present invention will now be described in detail with reference to the accompanying drawings.

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0035] like Figure 1As shown, a method for designing a custom interface for a collision integral transport model is presented. The method specifically includes the following steps:

[0036] Step S100: Construct a UDF parameter file based on the collision integral transport model. The components in the UDF parameter file can be arbitrarily combined for calculation, generally in pairs.

[0037] Based on various complex gas models, such as Earth's atmosphere, Martian atmosphere, high-temperature gas, and ablation ejector gas, common features of the calculation parameters of the collision integral transport model are extracted. UDF parameter files with standardized format, flexible editing, and easy reusability are established to realize the human-computer interactive parameter setting function.

[0038] For commonly used gas models in engineering, such as Earth's atmosphere, Martian atmosphere, high-temperature gas, and ablation ejection gas, the collision integral transport model mainly includes the following three types of information in its parameter system construction: I / O control variables, gas mixture composition, and component collisions. The set of parameters for calculation and fitting is used. Specifically, it is based on the five components of the Earth's atmosphere (O, ...). NO, N Taking the gas model as an example, the design template of the UDF parameter file for the general collision integral transport model is shown in Table 1.

[0039] Table 1. Format of UDF parameter file for the general collision integral transport model

[0040]

[0041] As can be seen from Table 1, the collision integral transport model UDF parameter file adds five parameters to the I / O control variable section: species_num, pair_num, collision_mode, diff_fit_num, and vis_fit_num. These parameters are placed in the first five lines of the file for memory pre-allocation. The specific meanings and comments of the five parameters are shown in Table 1.

[0042] The sixth line provides a list of names of the components in the mixed gas. The names of each component are separated by spaces or commas for easy identification and reading. Furthermore, the order of each component can be arbitrarily arranged and adjusted, and can be expanded, added, deleted, or reduced as needed for calculation. This ensures the maximum flexibility for model modification and updates.

[0043] Furthermore, each component collision pair is described in detail in groups of two lines thereafter. This section lists all the fitting parameters for the collision integral, with the first line specifying the names of the components involved in the collision, followed by the next line providing the set of fitting parameters for the collision integral. For example, lines 7-8 first give the component collision pairs. The two components involved in the collision, O and O', are listed in detail on the next line, along with their collision integral fitting parameters. Component symbols are separated by spaces or commas for easy identification and reading. Furthermore, the collision integral fitting parameters for inelastic Coulomb collisions typically consist of eight parameters (determined by `diff_fit_num=4` and `vis_fit_num=4`), divided into two parts: the first four values ​​(the specific number determined by `diff_fit_num`) are the diffusion collision integral fitting parameters for the collision pair OO, and the last four values ​​(the specific number determined by `vis_fit_num`) are the viscous collision integral fitting parameters for the collision pair OO. For Coulomb collisions, the fitting parameters for the diffusion and viscous collision integrals are `diff_fit_num=3` and `vis_fit_num=3`, respectively. Other component collision pairs... The examples will be given in turn.

[0044] It is worth noting that: component collision pairs The order of information listing is not fixed and can be freely written according to the user's needs. For example, the data information in lines 7 and 8 can be moved to any position after line 9, just be careful not to affect the integrity of other component collision pair information. That is, a collision pair contains 2 lines of data information, namely the collision pair itself. It provides a detailed list of component names and its set of fitting calculation parameters. Therefore, when users need to expand or reduce the number of mixed gases, adding relevant entries or deleting irrelevant collision pairs is more flexible and unaffected by the inherent order, while also improving the reusability of the component collision pair fitting calculation parameters.

[0045] In addition, UDF parameter files allow for component collision pairs Data is reused, but the last occurrence of the data will be used; previously given data will be replaced by later data. (Based on component collision pairs O-) For example, its data information first appears in rows 9-10 of Table 1. If two more rows are subsequently added at the end of Table 1 to similarly describe the component collision pairs O- If the parameter information is given, then when using the data, the last two rows of data will be used, and the data in rows 9 and 10 will be replaced. This is essentially equivalent to using the last data to determine the collision pair O-. The data information has been updated and modified. This capability is also due to the high reusability and extensibility of the UDF parameter file design.

[0046] At the same time, the components in a component collision pair are not ordered. The collision pairs O- and ji are considered to be in the same group of collisions, and their collision integral fitting calculation parameters are considered to be in the same group of data. For example, the collision pair O- Collision pairs with components -O represents the same group of collisions, therefore, "O- "and" The -O" correlation fitting calculation parameters are treated as the same set of data information in the UDF parameter file. If similar component collision pairs appear in later parts of the UDF parameter file... The information content of -O, then the component collisions mentioned earlier, O- The data parameters will also be affected by the component collision pairs. -O data update replacement.

[0047] Step S200: Based on the UDF parameter file of the collision integral transport model, construct a parameter reading and parsing interface for parsing the collision integral model; based on the UDF parameter file established in step S100, construct a storage data structure for parsing the calculation parameters of the collision integral model, and establish corresponding I / O member functions to uniformly design and manage the I / O parsing interface, thereby realizing the association and conversion between the calculation storage data and the UDF parameter file.

[0048] Based on the UDF parameter file design method in step S100, object-oriented programming principles are adopted to design the CollisionIntegralData class data structure for the collision integral model, thereby unifying the I / O parsing interface. The member variables and functions of the CollisionIntegralData class are described in Table 2 below.

[0049] Table 2. Description of member variables and functions of the CollisionIntegralData class in the chemical reaction model.

[0050]

[0051] like Figure 2As shown, based on the UDF parameter file and the CollisionIntegralData class data structure described in step S100, the I / O interface function first obtains the total number of gas components (species_num), the total number of component collision pairs (pair_num), the component collision type (collision_mode), the number of parameters for diffusion collision integral fitting calculation (diff_fit_num), and the number of parameters for viscous collision integral fitting calculation (vis_fit_num), and assigns values ​​to the member variables of the CollisionIntegralData class, namely nSpecies = species_num, nCollisionMode = collision_mode, nFitNum1 = diff_fit_num, and nFitNum2 = vis_fit_num. The data structure for the collision integral fitting calculation parameters uses a three-dimensional array. Since the maximum number of effective component collision pairs is only nSpecies(nSpecies+1) / 2, using a three-dimensional array data structure results in wasted data space, but it increases the convenience of parameter use and maintains consistency with the storage method of flow field parameters. Furthermore, the number of effective component collision pairs is related to the number of components. Therefore, the parameter pair_num does not need to be separately allocated as a member variable in the CollisionIntegralData class, but it can be used as a temporary variable to constrain the reading process of the UDF parameter file.

[0052] Secondly, the array space is initialized according to the above parameters. Among them, the size of the one-dimensional array speciesName is nSpecies, the size of each dimension of the three-dimensional array curveFitOmega11 is nSpecies, nSpecies and nFitNum1 respectively, and the size of each dimension of the three-dimensional array curveFitOmega22 is nSpecies, nSpecies and nFitNum2 respectively.

[0053] Next, we first read the name of each component and store it in the array `speciesName`. Then, based on the `pair_num` parameter, we iteratively read the collision pairs of each component. The fitting calculation parameters are obtained. Specifically, the collision components' indices (i and j) in the three-dimensional array space are obtained based on their component name strings. Then, the corresponding fitting calculation parameters are stored in the corresponding spaces of the three-dimensional arrays curveFitOmega11 and curveFitOmega22, respectively.

[0054] Step S300: Construct a mapping function interface from the collision integral transport model obtained from the UDF parameter file to the collision integral transport model required for actual flow simulation. Based on the composition and sorting of the mixed gas components provided by the master control parameter file, the optimized and recombined collision integral transport model parameters are obtained through the mapping function interface and used to perform thermochemical nonequilibrium flow iterative solution on the high-temperature nonequilibrium CFD solver.

[0055] This embodiment uses 5 components (O, NO, N Taking a gas model as an example, if the flow simulation of the gas mixture only contains O and If the calculation is still performed using a 5-component model with two components, then NO, N, and The storage space and computation time consumed by the three redundant components do not contribute to improving computational efficiency. Therefore, an optimized recombination mapping function interface was added to the program design, transforming the parameter system of the complete collision integral model into a minimized collision integral model parameter system. This function removes redundant components and irrelevant component collision pair parameter information, generating a simplified collision integral model and its parameter system, which can then be called and controlled by the high-temperature non-equilibrium CFD solver. The optimized and recombined collision integral model (i.e., the simplified parameter model) is shown in Table 3. It can be seen that the number of mixed gas components is reduced by 3, and the number of component collision pairs is reduced by 12, resulting in a significant improvement in storage space and computational efficiency.

[0056] Table 3. Parameter file templates for the 2-component collision integral transport model generated from the simplified mapping of the 5-component gas model.

[0057]

[0058] like Figure 3 As shown, users can arbitrarily delete or remove components from the mixed gas and rearrange component order according to the parameters set in the master control file, thereby obtaining simplified collision integral models with different component combinations. Therefore, this mapping function interface design makes the collision integral models more diverse and more flexible to use.

[0059] Step S400: Modify the UDF parameter file and its associated collision integral transport model and parameters according to the calculation needs, and obtain the thermochemical non-equilibrium steady-state flow field and parameter distribution by coupling with the flow field solver.

[0060] Based on the calculation conditions, the modified UDF parameter file and its associated collision integral transport model and parameters are applied to the numerical iteration process of the high-temperature nonequilibrium CFD solver to update the thermodynamic transport coefficients of the mixed gas components until the convergence conditions are met, thus obtaining the final required thermochemical nonequilibrium steady-state flow field and parameter distribution.

[0061] Thermodynamic transport coefficients mainly include viscosity coefficient, thermal conductivity coefficient and mass diffusion coefficient, while flow field parameter distribution includes wall pressure and heat flux density.

[0062] The thermochemical nonequilibrium flow control equations involved in the high-temperature nonequilibrium CFD solver are in the form of conserved integrals:

[0063] ;

[0064] in, , These represent the control volume and its bounding surface, respectively. To control the volume of the unit, The area of ​​the circulation surface. Let be the normal vector of the flow surface. For the incoming Reynolds number, For conserved quantities vector, and These are convective flux and viscous flux, respectively. For non-equilibrium source terms, For time.

[0065] Conserved vector Regarding circulation volume Viscous flux and unbalanced source terms The specific expression is:

[0066]

[0067] in, For the circulation area The normal vector, , Normal vectors Components along each coordinate axis direction, Let be the absolute velocity of the fluid. , These represent the component values ​​of velocity along each coordinate axis. Each component in the gas mixture The mass fraction, specific enthalpy, vibrational energy, and mass diffusion coefficient. , The total number of components in the gas mixture. These are the density, pressure, and temperature of the mixed gas, respectively. The total enthalpy of the mixed gas. The vibrational energy and total internal energy of the gas mixture. These are the translational mode thermal conductivity and the vibrational mode thermal conductivity of the mixed gas, respectively. Components The chemical reaction produces the source term. For vibration non-equilibrium source terms; For viscous stress tensor, Let each of the components of the viscous stress tensor be a separate value, and Satisfy the following formula:

[0068] ;

[0069] in, The viscosity coefficient of the mixed gas. Cartesian coordinate system Velocity component values ​​in three coordinate directions.

[0070] The specific correlation for the mixed gas energy system is as follows:

[0071] ;

[0072] in, These are the density, pressure, total specific internal energy, and enthalpy of the mixed gas, respectively. These represent the translational and vibrational kinetic energy of the gas mixture, respectively.

[0073] The viscosity coefficient, thermal conductivity coefficient, and mass diffusivity of the gas mixture are all calculated using the collision integral model. The calculation formula is:

[0074] ;

[0075] in, It is an electronic component. Mass of a single particle (unit: kg) , This refers to the index of the gas component in the set. Molar mass For Avogadro's constant, gaseous components molar concentration (unit: mol / kg). , gaseous components mass fraction, These represent translational temperature and electron temperature (unit: K), respectively. Indicates component collision pairs Viscous collision integral term (unit: ), Indicates component collision pairs Viscous collision integral term (unit: ), Indicates component collision pairs Viscous collision integral term (unit: ).

[0076] Thermal conductivity coefficients of translational and rotational energy and They are respectively:

[0077] ;

[0078] in, It is an electronic component. It is a multi-atomic component or molecule. Boltzmann's constant, , gaseous components molar concentration (unit: mol / kg). Indicates component collision pairs diffusion-collision integral term (unit: ), Indicates component collision pairs diffusion-collision integral term (unit: ), Indicates component collision pairs Viscous collision integral term (unit: ), Indicates component collision pairs Viscous collision integral term (unit: ).

[0079] coefficient Defined as:

[0080] ;

[0081] in, For mass ratio, gaseous components The mass of a single particle (unit: kg), gaseous components The mass of a single particle (unit: kg), gaseous components molar mass, gaseous components The molar mass.

[0082] Thermal conductivity coefficients of vibrational energy and electronic energy and They are respectively:

[0083] ;

[0084] in, It is a universal gas constant. The average molecular weight of the mixed gas. The vibrational isochoric specific heat of the gas mixture. The thermal conductivity coefficient of rotational energy. Boltzmann's constant, , This represents the molar concentration of electrons (unit: mol / kg). For electron temperature, The average molecular weight of the mixed gas. The electronic isochoric specific heat of the gas mixture. Indicates component collision pairs diffusion-collision integral term (unit: ).

[0085] Components Equivalent mass diffusion coefficient for:

[0086] ;

[0087] in, gaseous components The molar concentration (unit: mol / kg).

[0088] diffusion collision integral term and viscous collision integral term Calculate using the following formula:

[0089] ;

[0090] in, and For the component number, , Gas components and Molar mass of molecules Indicates component collision pairs The diffusion collision integral or diffusion collision cross section (unit: m2). Indicates component collision pairs Viscous collision integral or viscous collision cross section (unit: m2).

[0091] For inelastic collision types, the diffusion collision integral and viscous collision integral The following calculations were performed using a fitting method:

[0092] ;

[0093] Among them, the fitting coefficient , , , , , , , The parameters are determined by the collision integral fitting calculation parameters in the UDF parameter file.

[0094] The LU-SGS numerical scheme is used to discretize and iteratively solve the governing equations of thermochemical nonequilibrium flow. The flow field calculation is considered convergent when the average residual tends to plateau or the maximum number of iterations is reached, thus obtaining various parameters of the chemical nonequilibrium steady flow, such as wall pressure distribution and wall heat flux distribution. The LU-SGS numerical iterative scheme is expressed as follows:

[0095] ;

[0096] ;

[0097] Among them, superscript * indicates the calculation time, and * indicates intermediate calculation amount. The right-hand side is represented by L, D, and U, which are the lower triangular matrix, diagonal matrix, and upper triangular matrix, respectively. For the temporary conservation quantity to increase, For the present The increase in the conserved quantity calculated at each moment.

[0098] Example 1

[0099] like Figures 4-5 As shown, one embodiment of the present invention is a custom interface design method for a collision integral transport model, which is applied to setting collision integral model parameters in a high-temperature nonequilibrium CFD solver, and calculating thermodynamic transport coefficients such as viscosity coefficient, thermal conductivity coefficient, and mass diffusion coefficient. At the same time, it is used to conduct high-temperature and high-speed chemical nonequilibrium flow simulation based on the HEG shock tunnel cylindrical model. The calculation model and experimental conditions refer to existing calculation models and experimental conditions.

[0100] The complete 14-component collision integral model (O / ) is derived from the UDF parameter file. / NO / N / / / / / / / / C / CO / The numerical simulation uses a single-temperature thermodynamic five-component (O / ) input. / NO / N / The Dunn-Kang chemical model was used, with the Steger scheme and Minmod limiter selected for flux. The Courant number (CFL number) was set to 200, and the wall boundary was set to the isothermal fully catalytic wall condition (wall temperature 300K). The single-core serial iteration step number was 10,000.

[0101] Figure 4 and Figure 5 A comparison of wall pressure and heat flux distributions calculated using different methods is presented. The figures show that the wall pressure curve calculated using the method of this invention is consistent with the fitting calculation method. However, compared to experimental data, the wall pressure curve calculated using the method of this invention has higher accuracy in predicting heat flux distribution. This verifies the correctness and effectiveness of the collision integral transport model UDF parameter file and its parsed I / O interface constructed in this invention, demonstrating that the collision integral model interface design method described in this invention can meet the application requirements of chemical reaction flow simulation related to complex flight environments.

[0102] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for designing a custom interface for a collision integral transport model, characterized in that, The method specifically comprises the following steps: Step S100: constructing a UDF parameter file based on a collision integral transport model, and any combination of components in the UDF parameter file; Step S200: constructing a parameter reading and parsing interface of the analytical collision integral model based on the UDF parameter file of the collision integral transport model; Step S300: constructing a mapping function interface from the collision integral transport model obtained by the UDF parameter file to the collision integral transport model required for actual flow simulation; Step S400: modifying the UDF parameter file and its associated collision integral transport model and parameters according to the calculation requirements, and obtaining the thermally-chemically non-equilibrium steady flow field and parameter distribution through coupling calculation with a flow field solver; Step S100 specifically comprises: Based on various complex gas models, the common characteristics of the collision integral transport model calculation parameters are extracted, and a UDF parameter file is established; The UDF parameter file includes three types of information elements, i.e., I / O control variables, mixture composition configuration, and fitting calculation parameter set of components collision pairs and fitting calculation parameter set of components collision pairs Step S200 specifically comprises: Based on the UDF parameter file established in step S100, a storage data structure for parsing the collision integral model calculation parameters is constructed, and a matching I / O member function is established, and the I / O parsing interface is uniformly designed and managed; Step S300 specifically comprises: The mapping function interface from the collision integral transport model obtained by the UDF parameter file to the collision integral transport model required for actual flow simulation is constructed, the optimized recombined collision integral transport model parameters are obtained through the mapping function interface conversion according to the mixture gas component composition and ordering provided by the main control parameter file, and the thermally-chemically non-equilibrium flow iterative solution of the high-temperature non-equilibrium CFD solver is performed; Five parameters are added to the I / O control variable element, and the five newly added parameters are placed in the first five lines of the UDF parameter file for memory pre-allocation and parameter reading control; The five parameters are: species_num, pair_num, collision_mode, diff_fit_num and vis_fit_num; species_num is the total number of mixture gas components, pair_num is the total number of component collision pairs, collision_mode is the collision type, diff_fit_num is the number of diffusion collision integral fitting calculation parameters, and vis_fit_num is the number of viscosity collision integral fitting calculation parameters; Component collision pairs for udf parameter files and its fitted calculation parameter set section, a component collision pair contains 2 rows of data information, respectively, the detailed component name list of the component collision pair and its fitted calculation parameter set; UDF parameter file allows for component collision pairs re-use of data, later occurring identical component collision pairs data replaces earlier occurring component collision pairs data; and component collision pairs and component collision pairs are the same component collision pairs.

2. The method of claim 1, wherein, Step S400 specifically comprises: The modified UDF parameter file and its associated collision integral transport model and parameters are applied in the numerical iterative process of the high-temperature non-equilibrium CFD solver, the thermodynamic transport coefficients of the mixture gas components are updated, and the final required thermally-chemically non-equilibrium steady flow field and parameter distribution are obtained when the convergence condition is met.

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