A method, system, apparatus, and medium for high temperature flow field spectral emission characteristics

Abstract

The application provides a method, system, device and medium for high-temperature flow field air spectrum radiation characteristics, based on non-equilibrium gas radiation characteristic parameters, according to the principle that Doppler broadening and Lorentz broadening are independent of each other, a Voigt line type is adopted to determine a line function under a non-standard state, and based on the line function under the non-standard state, an absorption coefficient and an emission coefficient after superposition are obtained; based on the absorption coefficient and the emission coefficient, radiation intensity transmitted under different flow field gradients is obtained, a result error of the radiation intensity transmitted under the different flow field gradients is analyzed, and a flow field gradient required for radiation intensity calculation is determined; based on the flow field gradient, the absorption coefficient and the emission coefficient, a radiation exit intensity of a single point source is obtained by using a LOS method; a flow field slice is cut according to a transmission direction in a field, and the radiation exit intensity of each slice in a detection direction is calculated by using the LOS method and the flow field gradient; and attenuation calculation is performed on the radiation exit intensity, so that spatial and spectral distribution characteristics of radiation intensity of a target high-temperature flow field in a corresponding spectral interval are obtained.

Description

Technical Field

[0001] The present invention belongs to the field of spectral measurement technology, and mainly relates to a calculation model of high-temperature non-equilibrium gas radiation characteristic parameters and the expansion of radiation transmission characteristics. Specifically, it provides a method, system, equipment and medium for high-temperature flow field space spectrum radiation characteristics. Background Art

[0002] Radiative heat transfer dominates high-temperature systems, making rapid and reliable measurement or calculation of the spatial spectrum radiation characteristics of radiation sources a prerequisite for thermal performance analysis and target detection. Calculation of spatial spectrum radiation characteristics primarily involves four key aspects: accurate acquisition of gas radiation spectral data, efficient radiation characteristic calculation models, accurate solutions to multidimensional spatial radiation transfer equations, and spatial multi-point source calculations. The sheer number of gas radiation spectral lines and complex environmental background conditions significantly increase the computational complexity, severely impacting the reliability and efficiency of spatial spectrum measurements.

[0003] At present, the calculation of the spatial spectrum radiation characteristics of high-temperature flow fields mainly focuses on two aspects. The first aspect is to study the efficient calculation model of the radiation characteristic parameters of non-equilibrium gases and select an efficient calculation model of the radiation characteristic parameters; the second aspect is to study the solution of the multi-dimensional space radiation transfer equation for a single point source and determine the optimized solution of the radiation transfer equation by deducing different specific types of radiation transfer equations. The following explains the shortcomings of the above two aspects:

[0004] Currently, models for calculating gas radiation properties are primarily categorized into four categories: surrogate models, global models, band models, and line-by-line models. These models have been developed over the years and are relatively well-developed. However, due to the complex multi-physics coupling inherent in high-temperature gas radiation, existing models are more or less flawed. For example, surrogate models offer high computational efficiency, but their performance is limited by the mathematical methods employed. The calculated results contain uncertainties that are difficult to interpret, hindering in-depth analysis of spectral radiation properties. Global models consider only the overall radiation situation, treating the mixed gas as a gray body. They typically directly use the overall radiation characteristics to calculate the radiation heat flux, but this ignores spectral details and results in large errors. Band models improve computational efficiency at the expense of accuracy. Line-by-line models offer the highest computational accuracy, but involve a large number of spectral lines, making the solution more difficult. Spectral calculations of unknown radiation sources in complex backgrounds require as much and accurate information as possible. Therefore, high-precision line-by-line models are the preferred choice for calculating non-equilibrium gas radiation properties.

[0005] The existing solving methods of the multi-dimensional space radiation transfer equation mainly include the spherical harmonic method, the discrete ordinate method, the finite volume method, the line of sight (LOS) method, etc. The spherical harmonic method essentially uses the finite set of moment equation to approximately represent the radiation transfer equation. With the increase of the expansion order, the calculation accuracy of the method is improved, but the calculation complexity is also sharply increased accordingly. The principle of the discrete ordinate method is to divide the solid angle into a finite directional angle, convert the radiation transfer equation into a partial differential equation for calculation of a single directional angle, and finally couple the radiation intensity of different directional angles according to the source term, but the discrete angle needs to meet certain constraints. The finite volume method is an optimization of the discrete ordinate method, which belongs to a low-order method and can only improve the calculation accuracy by encrypting or re-dividing the grid. For the calculation of radiation transmission of non-gray, non-isothermal and non-uniform medium, the line of sight (LOS) method is the most widely used method.

[0006] In summary, the existing related technology lacks an accurate and efficient high-temperature non-equilibrium gas radiation characteristic parameter calculation and spatial multi-point source radiation transmission characteristic method in the full spectral range, which cannot realize efficient and accurate solving of the spatial and spectral distribution characteristics of the radiation intensity of the high-temperature flow field in the corresponding spectral interval. SUMMARY

[0007] In order to solve the problems in the prior art, the present application provides a high-temperature flow field air spectrum radiation characteristic method, system, device and medium, to solve the technical problem that the existing related technology lacks an accurate and efficient high-temperature non-equilibrium gas radiation characteristic parameter calculation and spatial multi-point source radiation transmission characteristic method in the full spectral range.

[0008] To achieve the above purpose, the present application provides the following technical solutions:

[0009] A high-temperature flow field air spectrum radiation characteristic method, comprising the following steps:

[0010] Based on the non-equilibrium gas radiation characteristic parameters, and according to the principle that the Doppler broadening and the Lorentz broadening are independent of each other, a Voigt line type is used to determine a line function under a non-standard state, and based on the line function under the non-standard state, an absorption coefficient and an emission coefficient after superposition are obtained;

[0011] Based on the absorption coefficient and the emission coefficient, the radiation intensity transmitted under different flow field gradients is obtained, the result error of the radiation intensity transmitted under different flow field gradients is analyzed, and the flow field gradient required for radiation intensity calculation is determined;

[0012] Based on the flow field gradient, the absorption coefficient and the emission coefficient, the radiation exit intensity of a single point source is obtained by using the LOS method;

[0013] Slicing the flow field according to the in-field transmission direction, calculating the radiation exit intensity of each slice in the detection direction by using the LOS method and the flow field gradient;

[0014] Determining the detection direction and detection waveband of the target high-temperature flow field, determining the atmospheric transmission transmittance at the flight height according to the flight height and the atmospheric transmission distance, and performing attenuation calculation on the radiation exit intensity to obtain the spatial and spectral distribution characteristics of the radiation intensity of the target high-temperature flow field in the corresponding spectral range.

[0015] Further, the non-equilibrium gas radiation characteristic parameters are preprocessed, and the preprocessing includes the following steps:

[0016] Calculating the spectral line intensity S(T) under the non-standard state: for the intensity S(T) of the spectral line at the wave number η0 under the temperature T and the pressure P, the intensity S(T) is expressed as:

[0017]

[0018] In the formula, P0 is the pressure under the standard state; T0 is the temperature; T ve is the electronic-vibrational temperature; h is the Planck constant; c is the light speed; k is the Boltzmann constant; P tot is the actual total pressure of the gas; S(T0) is the line intensity under the standard state; η0 is the wave number; N0 is the number of molecules per unit volume under the standard state; Q(T0, T0) is the total partition function under the double temperature; E” is the transition low-state energy;

[0019] Calculating the partition function of the molecule at the translational-rotational temperature T tr and the electronic-vibrational temperature T ve , and the expression is as follows:

[0020]

[0021] In the formula, E el (n) is the electronic energy level of the molecule; E vib (n, v) is the vibrational energy level of the molecule; E rot (n, v, J) is the rotational energy level of the molecule; E v,0 is the vibrational energy corresponding to the electronic state n, v = 0; σ is the symmetry factor, σ = 1 for heteronuclear molecules and σ = 2 for homonuclear molecules; (2-δ Λ,0 )(2S+1) is the statistical weight of the electronic energy level; (2J+1) is the degeneracy of the rotational energy level;

[0022] The non-equilibrium gas molecular particle density at the translational-rotational temperature T tr and the electronic-vibrational temperature T ve is calculated as follows:

[0023]

[0024] The calculation of the vibrational energy term value G and the rotational energy term value F, unit (cm-1):

[0025]

[0026] F(J) = B ν J(J+1)-D ν J 2 (J+1) 2 +H ν J 3 (J+1) 3 +…

[0027] In the formula, g e is the electronic statistical weight; g e = g l / (2J l +1), g l is the degeneracy of the low energy level; J l is the rotational quantum number of the low energy level; ΔE e , ΔE v , ΔE J” are the electronic energy term value, the vibrational and rotational energy term value respectively, unit J.

[0028] Further, according to the principle that Doppler broadening and Lorentz broadening are independent of each other, a Voigt line type is adopted to determine the line shape function under non-standard state, and the process of obtaining the superimposed absorption coefficient and emission coefficient based on the line shape function under non-standard state is as follows:

[0029] The broadening line shape function F(η-η0) of the spectral line with the center wave number η0 at the wave number η is calculated:

[0030] According to the characteristics that Doppler broadening and Lorentz broadening are independent of each other, the Voigt line type is adopted to approximately calculate the broadening line shape function F(η-η0), and the expression is as follows:

[0031]

[0032] In the formula, W L , W D , W V are the spectral line half-width of Lorentz broadening, Doppler broadening and Voigt line type respectively;

[0033] The absorption coefficient and emission coefficient of the non-equilibrium gas under the bound-bound, bound-free and free-free transition mechanisms are calculated respectively:

[0034]

[0035] In the formula, ηul is the transition wave number, cm -1 ; A ul is the Einstein spontaneous transition coefficient, s -1 ; g u and g l are the degeneracy of the upper and lower energy levels, respectively; N u and N l are the population of gas particles on the upper and lower energy levels, cm -3 ; ∑α η = ∑S(T)N i F(η) is the spectral line shape function; N at is the total number of atoms; Q at is the atomic partition function; m e is the mass of an electron, g k is the degeneracy of the energy level k, S k (η) refers to the total absorption cross section on the energy level k, g(η, T) is the Gaunt factor, whose expression is Z is the atomic number, N e and N ion are the densities of electrons and ions, respectively.

[0036] Further, the result error of the transmitted radiation intensity under different flow field gradients is analyzed, including the following steps:

[0037] The corresponding non-equilibrium gas radiation physical parameters under different gradient distributions are calculated, and the total absorption coefficient and emission coefficient after superposition are calculated:

[0038]

[0039] In the formula, η 0i is the central wave number of the i-th spectral line; Si is the intensity of the i-th spectral line at the central wave number η 0i ; F(η-η 0i ) is the spectral line shape function;

[0040] Nine surface elements are divided at the shock layer of the high-temperature flow field, different gradient distributions are set, and the radiation exit intensity of each is calculated by the LOS method:

[0041]

[0042] The calculation time of each gradient is recorded, and the calculation accuracy of the radiation intensity under each gradient is analyzed, and the best flow gradient distribution is selected under the premise of ensuring the accuracy and reliability of the calculation results;

[0043] In the formula, indicates the directional spectral radiation intensity of the nth layer; represents the transmittance of the nth layer of medium; L is the path length of the light in the nth layer of medium, and to be replaced by the emission coefficient ε(η).

[0044] Further, the process of obtaining the radiant exitance of the single point source is:

[0045] Taking the flow field environmental variable Data: the flow field medium on the transmission path is divided into 10 layers, each layer is regarded as an isothermal and uniform medium, and the average flow field parameter Data1-Data10 of each layer is taken;

[0046] Starting from the flow field thickness, the spectral radiant exitance of the shock layer single point source is solved by the LOS method based on the average flow field parameter Data1-Data10 of each layer:

[0047]

[0048] wherein, is the directional spectral radiant intensity of the nth layer; represents the transmittance of the nth layer of medium; is the emission coefficient.

[0049] Further, the process of calculating the radiant exitance of each slice in the detection direction is:

[0050] According to the transmission direction of radiation in space, the entire flow field is accurately geometrically divided to form a series of slices, each of which has a clear boundary in space and can represent the local characteristics of the flow field in that direction;

[0051] On each of the slices, a series of coordinate points are defined, which will be used to calculate the radiant exitance. The coordinate points uniformly cover the entire slice area.

[0052] The radiant exitance of the coordinate points on each slice is calculated by solving the radiation transfer equation using the LOS method, and the position of the coordinate points and the corresponding radiant intensity values calculated are stored.

[0053] Further, the process of obtaining the spatial and spectral distribution characteristics of the radiant intensity of the target high-temperature flow field in the corresponding spectral range is:

[0054] The detection direction and the detection waveband are determined, the detection direction determines the viewing angle of the radiation calculation, and the selection of the detection waveband involves the spectral resolution of the radiation, which determines the type and characteristics of the detected radiation.

[0055] According to the flight height, the atmospheric transmission distance is set, the atmospheric transmission transmittance is calculated by using a radiation transmission model MODTRAN, and the radiation exit intensity at all the slice points is calculated by using the atmospheric transmission transmittance for attenuation.

[0056] According to the spatial and spectral distribution characteristics of the radiation intensity of the target high-temperature flow field in the corresponding spectral range, the spatial and spectral radiation characteristics of the target high-temperature flow field are modeled, and the spatial and spectral distribution characteristics of the radiation intensity of the target high-temperature flow field in the corresponding spectral range are obtained based on the modeling of the spatial and spectral radiation characteristics.

[0057] A system for spatial and spectral radiation characteristics of a high-temperature flow field, comprising:

[0058] The first processing unit is configured to:

[0059] The first processing unit is configured to:

[0060] The second processing unit is configured to:

[0061] The second processing unit is configured to:

[0062] The third processing unit is configured to:

[0063] The third processing unit is configured to:

[0064] The fourth processing unit is configured to:

[0065] The fourth processing unit is configured to:

[0066] The output unit is configured to:

[0067] The output unit is configured to:

[0068] A computer device comprises a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the method for high-temperature flow field spectral radiation characteristics.

[0069] A computer-readable storage medium stores a computer program, wherein the computer program is executable by a processor to implement the steps of the method for high-temperature flow field spectral radiation characteristics.

[0070] Compared with the prior art, the present application has the following beneficial technical effects:

[0071] The present application provides a method, system, device and medium for high-temperature flow field spectral radiation characteristics, comprising the following steps: based on non-equilibrium gas radiation characteristic parameters, and according to the principle that Doppler broadening and Lorentz broadening are independent of each other, a Voigt line type is adopted to determine a line function under a non-standard state, and absorption coefficients and emission coefficients after superposition are obtained based on the line function under the non-standard state; radiation intensity transmitted under different flow field gradients is obtained based on the absorption coefficients and emission coefficients, and the result error of the radiation intensity transmitted under different flow field gradients is analyzed to determine the flow field gradient required for radiation intensity calculation; radiation exit intensity of a single point source is obtained based on the flow field gradient, absorption coefficients and emission coefficients using the LOS method; the flow field is sliced according to the transmission direction in the field, and the radiation exit intensity of each slice in the detection direction is calculated using the LOS method and the flow field gradient; the detection direction and detection waveband of the target high-temperature flow field are determined, the atmospheric transmission transmittance at the flight height is determined according to the flight height and atmospheric transmission distance, the radiation exit intensity is calculated for attenuation, and the spatial and spectral distribution characteristics of the radiation intensity of the target high-temperature flow field in the corresponding spectral interval are obtained; the present application can efficiently calculate the radiation transmission characteristic parameters under given conditions based on non-equilibrium gas radiation characteristic parameters; the flow field gradient distribution analysis can realize high-reliability and high-efficiency spectral radiation characteristic calculation when expanding the spatial multi-point source calculation, improve the calculation efficiency, and guarantee the calculation accuracy; and the spatial position, radiation intensity and other detailed information of the flow field are retained when calculating the high-temperature flow field spectral radiation characteristics, the observation spectral band and atmospheric transmission distance can be adjusted as needed, and the method is suitable for calculating the spatial and spectral distribution characteristics of the radiation intensity of the high-temperature flow field in the corresponding spectral interval under different detection directions, and the calculation results can lay a data foundation for subsequent thermal performance analysis and target detection. BRIEF DESCRIPTION OF DRAWINGS

[0072] Figure 1 A method flow chart for high-temperature flow field spectral radiation characteristics is shown;

[0073] Figure 2 A high-temperature flow field spectral radiation characteristic modeling method schematic diagram is shown

[0074] Figure 3 shows a radiation intensity diagram under different flow field gradient distributions under given conditions of an embodiment of the present disclosure;

[0075] Figure 4 A slice diagram of a high-temperature flow field under side observation under given conditions of an embodiment of the present disclosure is shown;

[0076] Figure 5 A diagram showing the radiation property parameters of high-temperature non-equilibrium gas under given conditions according to an embodiment of the present disclosure is shown;

[0077] Figure 6 It shows that all components under the given conditions of the embodiment of the present disclosure are in the range of 1000-150000 cm -1 The total spectral emission coefficient and absorption coefficient diagram below;

[0078] Figure 7 The figure shows the spatial spectrum radiation characteristics of the high-temperature flow field in the spectral range of 3-5 μm under the head-on observation of the embodiment of the present disclosure;

[0079] Figure 8 The figure shows the spatial spectrum radiation characteristics of the high-temperature flow field in the head-on observation range of 0.2-0.4 μm according to the embodiment of the present disclosure;

[0080] Figure 9 The figure shows the spatial spectrum radiation characteristics of the high-temperature flow field in the spectral range of 3-5 μm under the positive side direction observation of the embodiment of the present disclosure;

[0081] Figure 10 The high-temperature flow field spatial spectrum radiation characteristics in the spectral range of 0.2-0.4 μm under the positive side direction observation of the embodiment of the present disclosure are shown. DETAILED DESCRIPTION

[0082] Hereinafter, only certain exemplary embodiments are briefly described. As will be appreciated by those skilled in the art, the described embodiments may be modified in various ways without departing from the spirit or scope of the present invention. Therefore, the drawings and description are to be regarded as illustrative in nature and not restrictive.

[0083] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0084] It will be understood that when used in this specification and the appended claims, the terms “comprises” and “comprising” indicate the presence of described features, integers, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0085] It should also be understood that the terms used in the present specification are only for the purpose of describing particular embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0086] It should be further understood that the term "and / or" used in the present description and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

[0087] The accompanying drawings illustrate various schematic diagrams of structures according to embodiments disclosed herein. These figures are not drawn to scale; for clarity, some details are exaggerated and some details may be omitted. The shapes of the various regions and layers shown in the figures, as well as their relative sizes and positional relationships, are merely exemplary and may deviate in practice due to manufacturing tolerances or technical limitations. Those skilled in the art may design regions / layers with different shapes, sizes, and relative positions as needed.

[0088] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0089] Figure 1 A flow chart of a method for determining the spatial spectrum radiation characteristics of a high-temperature flow field according to an embodiment of the present disclosure is shown. Figure 1 As shown, the following steps are included:

[0090] Step S1: Based on the non-equilibrium gas radiation characteristic parameters and the principle that Doppler broadening and Lorentz broadening are independent of each other, a Voigt line shape is used to determine a line shape function under a non-standard state, and a superimposed absorption coefficient and emission coefficient are obtained based on the line shape function under the non-standard state;

[0091] Preferably, in the embodiment of the present disclosure, the non-equilibrium gas radiation characteristic parameters are preprocessed, and the preprocessing includes the following steps:

[0092] Calculate the spectral line intensity S(T) under non-standard conditions: For temperature T and pressure P, the intensity S(T) of the spectral line at wave number η0 is expressed as:

[0093]

[0094] where P0 is the pressure at standard state; T0 is the temperature; T ve is the electronic-vibrational temperature; h is the Planck constant; c is the speed of light; k is the Boltzmann constant; P tot is the actual total pressure of the gas; S(T0) is the line strength at standard state; η0 is the wave number; N0 is the number of molecules per unit volume at standard state; Q(T0, T0) is the total partition function at double temperature; E" is the lower state energy of the transition;

[0095] The partition function of the molecule at the translational-rotational temperature T tr and the electronic-vibrational temperature T ve is calculated as follows:

[0096]

[0097] where E el (n) is the electronic energy level of the molecule; E vib (n, v) is the vibrational energy level of the molecule; E rot (n, v, J) is the rotational energy level of the molecule; E v,0 is the vibrational energy corresponding to the electronic state n, v = 0; σ is the symmetry factor, σ = 1 for heteronuclear molecules and σ = 2 for homonuclear molecules; (2-δ Λ,0 )(2S+1) is the statistical weight of the electronic energy level; (2J+1) is the degeneracy of the rotational energy level;

[0098] The particle density of the non-equilibrium gas molecule at the translational-rotational temperature T tr and the electronic-vibrational temperature T ve is calculated as follows:

[0099]

[0100] The calculation of the vibrational energy term value G and the rotational energy term value F, in units of cm-1:

[0101]

[0102] F(J) = B ν J(J+1) - D ν J 2 (J+1) 2 + H ν J 3 (J+1) 3 +...

[0103] where g e is the electronic statistical weight; g e = g l / (2J l +1), g lJ l J e J v J J” are the electronic energy term value, the vibrational and rotational energy term value, respectively, in J.

[0104] Further in the embodiments of the present disclosure, according to the principle that Doppler broadening and Lorentz broadening are independent of each other, a Voigt line type is adopted to determine a line type function under a non-standard state, and a process of obtaining the superimposed absorption coefficient and emission coefficient based on the line type function under the non-standard state is as follows:

[0105] A broadening line type function F(η-η0) of a spectral line with a center wave number η0 at a wave number η is calculated:

[0106] According to the characteristics that Doppler broadening and Lorentz broadening are independent of each other, a Voigt line type is adopted to approximately calculate the broadening line type function F(η-η0), and an expression is as follows:

[0107]

[0108] In the formula, W L , W D and W V are the spectral line half-widths of Lorentz broadening, Doppler broadening and Voigt line type, respectively;

[0109] The absorption coefficient and emission coefficient of a non-equilibrium gas under the bound-bound, bound-free and free-free transition mechanisms are calculated respectively:

[0110]

[0111] In the formula, η ul is a transition wave number, cm -1 ; A ul is an Einstein spontaneous transition coefficient, s -1 ; g u and g l are the degeneracy of the high energy level and the low energy level, respectively; N u and N l are the gas particle populations on the high energy level and the low energy level, cm -3 ; ∑α η =∑S(T)N i F(η) is a spectral line type function; N at is the total number of atoms; Q at is an atomic partition function; m e is the mass of an electron, g k is the degeneracy of the energy level k, and S k(η) refers to the total absorption cross section on energy level k, g(η, T) is the just factor, and its expression is Z is the atomic number, N e and N ion are the densities of electrons and ions, respectively.

[0112] Step S2: obtaining the radiation intensity transmitted under different flow field gradients based on the absorption coefficient and the emission coefficient, analyzing the result error of the radiation intensity transmitted under different flow field gradients, and determining the flow field gradient required for radiation intensity calculation;

[0113] Preferably, in the embodiments of the present disclosure, the analysis of the result error of the radiation intensity transmitted under different flow field gradients comprises the following steps:

[0114] corresponding non-equilibrium gas radiation physical parameters under different gradient distributions are calculated, and the total absorption coefficient and the emission coefficient after superposition are calculated:

[0115]

[0116] In the formula, η 0i is the central wave number of the ith spectral line; Si is the intensity of the ith spectral line at the central wave number η 0i ; F(η-η 0i ) is a spectral line broadening function;

[0117] Nine surface elements are divided at the high-temperature flow field shock layer, different gradient distributions are set, and the radiation exit intensity of each is calculated by using the LOS method:

[0118]

[0119] The calculation time of each gradient is recorded, and the calculation accuracy of the radiation intensity under each gradient is analyzed, and the best flow gradient distribution is selected under the premise of ensuring the accuracy and reliability of the calculation results.

[0120] In the formula, represents the directional spectral radiation intensity of the nth layer; represents the transmittance of the nth layer medium; L is the path length of light transmission in the nth layer medium, and when in a non-equilibrium state, The emission coefficient ε(η) is replaced.

[0121] Step S3: obtaining the radiation exit intensity of a single point source by using the LOS method based on the flow field gradient, the absorption coefficient and the emission coefficient;

[0122] Preferably, in the embodiments of the present disclosure, the process of obtaining the radiation exit intensity of a single point source is as follows:

[0123] Data: the flow field medium on the transmission path is divided into 10 layers, each layer is regarded as an isothermal and uniform medium, and the average flow field parameter of each layer is taken as Data1-Data10;

[0124] Based on the average flow field parameter of each layer Data1-Data10, the spectral radiation exit intensity of the shock layer single-point source is solved by the LOS method from the flow field thickness:

[0125]

[0126] In the formula, is the directional spectral radiation intensity of the nth layer; represents the transmittance of the nth layer medium; is the emission coefficient.

[0127] Step S4: the flow field is sliced according to the in-field transmission direction, and the radiation exit intensity of each slice in the detection direction is calculated by using the LOS method and the flow field gradient;

[0128] Preferably, in the embodiments of the present disclosure, the process of calculating the radiation exit intensity of each slice in the detection direction is as follows:

[0129] According to the transmission direction of radiation in space, the entire flow field is accurately geometrically divided to form a series of slices, each of which has a clear boundary in space and can represent the local characteristics of the flow field in this direction;

[0130] On each slice, a series of coordinate points are defined, which will be used to calculate the radiation exit intensity, and the coordinate points uniformly cover the entire slice area;

[0131] The radiation transfer equation is solved by using the LOS method to calculate the radiation exit intensity of the coordinate points on each slice, and the position of the coordinate points and the corresponding radiation intensity value calculated are stored.

[0132] Step S5: the detection direction and detection waveband of the target high-temperature flow field are determined, the atmospheric transmission transmittance at the flight height is determined according to the flight height and atmospheric transmission distance, the radiation exit intensity is attenuated and calculated, and the spatial and spectral distribution characteristics of the target high-temperature flow field in the corresponding spectral interval are obtained.

[0133] Preferably, in the embodiments of the present disclosure, the process of obtaining the spatial and spectral distribution characteristics of the target high-temperature flow field in the corresponding spectral interval is as follows:

[0134] The detection direction and detection waveband are determined, the detection direction determines the viewing angle of radiation calculation, and the selection of the detection waveband involves the spectral resolution of radiation, which determines the type and characteristics of the detected radiation;

[0135] According to the flight height, the atmospheric transmission distance is set, the atmospheric transmission transmittance is calculated by using a radiation transmission model MODTRAN, and the radiation exit intensity at all of the slice points is calculated by using the atmospheric transmission transmittance for attenuation.

[0136] According to the spatial and spectral distribution characteristics of the radiation intensity of the target high-temperature flow field in the corresponding spectral range, the spatial and spectral radiation characteristics of the target high-temperature flow field are modeled, and the spatial and spectral distribution characteristics of the radiation intensity of the target high-temperature flow field in the corresponding spectral range are obtained based on the modeling of the spatial and spectral radiation characteristics.

[0137] The embodiment of the present disclosure provides a method for spatial and spectral radiation characteristics of a high-temperature flow field, which can obtain an efficient and accurate modeling scheme for the spatial and spectral radiation characteristics of the high-temperature flow field. The non-equilibrium gas radiation property parameters under a given condition are modeled by using a line-by-line model and a two-temperature model, the spatial and spectral radiation characteristics of the high-temperature flow field are obtained by using the LOS method based on the radiation property parameters of the non-equilibrium gas, and effective basis is provided for subsequent thermal performance analysis and target detection.

[0138] The embodiment of the present disclosure also provides a modeling scheme for the spatial and spectral radiation characteristics of the high-temperature flow field with high reliability and high efficiency. The modeling method is as shown in the figure, a database of non-equilibrium gas radiation characteristic parameters under different temperature gradients, pressures and mole fractions is established, the calculation efficiency under different flow field gradients is analyzed based on the database by using the LOS method, the solution of the radiation transfer equation is optimized, the spatial multi-point source calculation is expanded, the radiation exit intensity at all of the slice points is calculated, the spatial and spectral distribution characteristics of the ultraviolet and near-infrared wave bands in the non-equilibrium flow field are investigated, and effective basis is provided for subsequent thermal performance analysis and target detection. Figure 2

[0139] Specifically, the non-equilibrium gas radiation characteristic parameters are preprocessed, and accurate non-equilibrium spectral parameters can be obtained after the preprocessing. The preprocessing includes the following steps:

[0140] The spectral line intensity S(T) under the non-standard state is calculated: for the intensity S(T) of the spectral line at the wave number η0 under the temperature T and the pressure P, the intensity S(T) can be expressed as:

[0141]

[0142] wherein, the pressure P0 under the standard state is 1.01325×105 Pa, the temperature T0 is 296 K; T ve is the electron-vibration temperature, the Planck constant h is 6.63×10-34 J·s, the speed of light c is 3×108 m / s, and the Boltzmann constant k is 1.3806505×10-23 J / K; P tot ​where P is the total pressure of the gas, S(T0) is the line strength at standard state, the spectral databases HITEMP and CDSD provide the line strength S(T0) of a single molecule at wave number η0, N0 is the number of molecules per unit volume at standard state, N0 = 2.479 x 1019 molecule cm-3, Q(T0, T0) is the total partition function at double temperature, and E" is the transition low state energy, which can be obtained by querying the spectral database.

[0143] The partition function of the molecule at the translational-rotational temperature T tr and the electronic-vibrational temperature T ve is calculated, and the expression is as follows:

[0144]

[0145] where E el (n), E vib (n, v), and E rot (n, v, J) are the electronic energy level, the vibrational energy level, and the rotational energy level of the molecule; E v,0 is the vibrational energy corresponding to the electronic state n, v = 0; σ is a symmetry factor, σ = 1 for a heteronuclear molecule and σ = 2 for a homonuclear molecule; (2-δ Λ,0 )(2S+1) is the statistical weight of the electronic energy level; and (2J+1) is the degeneracy of the rotational energy level.

[0146] The non-equilibrium gas molecular particle density at the translational-rotational temperature T tr and the electronic-vibrational temperature T ve is calculated, and the expression is as follows:

[0147]

[0148] where g e is the electronic statistical weight, g e = g l / (2J l +1), g l is the degeneracy of the low energy level, J l is the rotational quantum number of the low energy level; ΔE e , ΔE v , and ΔE J” are the values of the electronic energy item, the vibrational energy item, and the rotational energy item, respectively, and the unit is J.

[0149] The calculation of the vibrational energy item G and the rotational energy item F, with the unit (cm-1):

[0150]

[0151] F(J) = B ν J(J+1) - Dν J 2 (J+1) 2 +H ν J 3 (J+1) 3 +…(5)

[0152] where ν is the vibrational quantum number, ω e , ω e χ e , ω e y e , ω e z e are spectral constants, which have different values for different electronic states; J is the rotational quantum number; B ν is the inertial rotation constant, D ν and H ν are centrifugal distortion constants.

[0153] Further, according to the principle that Doppler broadening and Lorentz broadening are independent of each other, a Voigt line type is adopted to determine a line shape function under a non-standard state, and a process of obtaining the superimposed absorption coefficient and emission coefficient based on the line shape function under the non-standard state includes the following steps.

[0154] A broadening line shape function F(η-η0) of a spectral line with a center wave number η0 at a wave number η is calculated: according to the characteristics that Doppler broadening and Lorentz broadening are independent of each other, the Voigt line type is adopted to approximately calculate the broadening line shape function F(η-η0), and an expression is as follows:

[0155]

[0156] where W L , W D , and W V are spectral line half-widths of Lorentz broadening, Doppler broadening, and Voigt line type respectively, and expressions are as follows:

[0157]

[0158] The absorption coefficient and emission coefficient of the non-equilibrium gas under the bound-bound, bound-free, and free-free transition mechanisms are respectively calculated:

[0159]

[0160] In the above formulae: η ul is a transition wave number, cm -1 ; A ul is an Einstein spontaneous transition coefficient, s -1 ; g u and g l respectively represent degeneracy of high and low energy levels. Nu and N l are the population of gas particles on high and low energy level, cm -3 ;∑α η =∑S(T)N i F(η) is the spectral line shape function.

[0161]

[0162] where N at is the total number of atoms, Q at is the partition function of atom, m e is the mass of electron, g k is the degeneracy of energy level k, S k (η) refers to the total absorption cross section on energy level k, which can be found in TOPBASE database.

[0163]

[0164] where g(η, T) is the Gaunt factor. Its expression is Z is the atomic number, N e and N ion are the density of electron and ion respectively.

[0165] Further, the analysis of the error of the results of the radiation intensity transmitted under different flow field gradients comprises the following steps:

[0166] corresponding non-equilibrium gas radiation physical parameters under different gradient distributions are calculated, and the total absorption coefficient and emission coefficient after superposition are calculated.

[0167]

[0168] η 0i is the central wave number of the i-th spectral line; Si is the intensity of the i-th spectral line at the central wave number η 0i ; F(η-η 0i ) is the spectral line broadening line shape function.

[0169] Nine surface elements are divided at the shock layer of high temperature flow field, different gradient distributions are set, and the radiation exit intensity of each is calculated by using the LOS method

[0170]

[0171] In the formula, represents the directional spectral radiation intensity of the n-th layer; represents the transmittance of the n-th layer medium; L is the path length of light transmission in the n-th layer medium. And in the non-equilibrium state, the emission coefficient ε(η) is replaced.

[0172] The calculation time of each gradient is recorded while analyzing the calculation accuracy of the radiation intensity under each gradient, and the calculation results are shown in Figure 3 It can be seen from the comparison that the radiation intensity increases with the increase of the flow field gradient. When the flow field gradient reaches 10, the radiation intensity no longer changes with the flow field gradient. Therefore, in order to balance efficiency and accuracy, and ensure the accuracy and reliability of the results, the flow field gradient is set to 10 in the subsequent calculation.

[0173] Further, the process of obtaining the radiation emission intensity of the single point source comprises the following steps:

[0174] Taking the flow field environment variable Data: The flow field medium on the transmission path is divided into 10 layers, and each layer is regarded as an isothermal and uniform medium. The average flow field parameter Data1-Data10 of each layer is taken.

[0175] Starting from the flow field thickness, the spectral radiation emission intensity of the shock layer single point source is solved by the LOS method based on the average flow field parameter Data1-Data10 of each layer

[0176]

[0177] Further, as shown in Figure 4 The process of calculating the radiation emission intensity of each slice in the detection direction comprises the following steps:

[0178] According to the transmission direction of radiation in space, the entire flow field is accurately geometrically divided to form a series of slices. Each slice has a clear boundary in space and can represent the local characteristics of the flow field in that direction.

[0179] On each slice, a series of coordinate points are defined, which will be used to calculate the radiation emission intensity. The coordinate points uniformly cover the entire slice area.

[0180] The radiation transfer equation is solved by the LOS method to calculate the radiation emission intensity of the coordinate points on each slice. The positions of the coordinate points and the corresponding radiation intensity values calculated are stored.

[0181] Further, the process of obtaining the spatial and spectral distribution characteristics of the radiation intensity of the target high-temperature flow field in the corresponding spectral range comprises the following steps:

[0182] The detection direction and the detection waveband are determined. The detection direction determines the viewing angle of the radiation calculation, and the selection of the detection waveband involves the spectral resolution of the radiation, which determines the type and characteristics of the detected radiation.

[0183] According to the flight height, the atmospheric transmission distance is set, the atmospheric transmission transmittance is calculated by using a radiation transmission model MODTRAN, and the radiation exit intensity at all the slice points is calculated by using the atmospheric transmission transmittance for attenuation.

[0184] According to the spatial and spectral distribution characteristics of the radiation intensity of the target high-temperature flow field in the corresponding spectral range, the spatial and spectral radiation characteristics of the target high-temperature flow field are modeled, and the spatial and spectral distribution characteristics of the radiation intensity of the target high-temperature flow field in the corresponding spectral range are obtained based on the modeling of the spatial and spectral radiation characteristics.

[0185] Further, the spatial and spectral radiation characteristics of the high-temperature flow field are modeled, and the calculation results are visualized by a spectral diagram to intuitively display the spatial and spectral radiation characteristics of the high-temperature flow field.

[0186] The technical effects of the present application are described below through simulation.

[0187] Simulation conditions:

[0188] The height of a point of the high-temperature flow field is selected as 61 km, the temperature T r = 13437.41 K, T v = 8640.77 K, and the pressure is 1.4 atm to analyze the radiation mechanism, and the spectral database adopts NIST, TOPBASE and HITRAN. The considered radiation process is as shown in Table 1:

[0189] Table 1.

[0190]

[0191] Simulation results and analysis:

[0192] Referring to Figure 5 , Figure 5 is the radiation property parameter diagram of the high-temperature non-equilibrium gas obtained by the present application, wherein the red line is the calculation result of the radiation characteristics of the high-temperature flow field mixed gas by the method proposed in the present patent, and the blue line is the calculation result in the literature. It can be seen that the calculation result of the present patent has high similarity with the literature result, and the peak values of some transitions are different, which may be caused by the difference of the selected database and the gas components, but the overall change trend shows that the method proposed in the present patent can be used to solve the spectral radiation characteristics of the high-temperature non-equilibrium gas. Thus, data basis is provided for subsequent spatial and spectral radiation characteristic analysis and calculation.

[0193] Referring to Figure 6 , Figure 6 is the total spectral emission coefficient and absorption coefficient of all components in the present application under 1000-150000 cm -1 , Figure 6 the horizontal axis represents the wave number, wherein Figure 6The vertical axis of (a) represents the emission coefficient, wherein Figure 6 The vertical axis of (b) represents the absorption coefficient. By Figure 6 It can be observed that in the infrared band, the continuous transition of N, O atoms and the infrared band of NO have a greater contribution to the absorption coefficient. In the near-infrared and visible light bands, the discrete transition of N, O atoms and the transition of N2 have a greater contribution to the absorption coefficient. In the ultraviolet and ultraviolet bands, the discrete transition of atoms and the photoionization transition of O2 have a greater contribution to the absorption coefficient. Thus, a foundation is laid for subsequent related research on the calculation and analysis of spectral radiation characteristics.

[0194] Referring to Figure 7 , Figure 8 , Figure 7 , Figure 8 are high-temperature flow field spectral radiation characteristics in the spectral range of 3-5 μm and 0.2-0.4 μm calculated by the present application under head-on direction observation, as shown in Figure 7 (a) and Figure 8 (a) respectively represent the spectral radiation under the condition of 61 km, Figure 7 (b) and Figure 8 (b) respectively represent the spectral radiation under the condition of 71 km, Figure 7 (c) and Figure 8 (c) respectively represent the spectral radiation under the condition of 81 km.

[0195] Referring to Figure 9 , Figure 10 , Figure 9 , Figure 10 are high-temperature flow field spectral radiation characteristics in the spectral range of 3-5 μm and 0.2-0.4 μm calculated by the present application under head-on direction observation, as shown in Figure 9 (a) and Figure 10 (a) respectively represent the spectral radiation under the condition of 61 km, Figure 9 (b) and Figure 10 (b) respectively represent the spectral radiation under the condition of 71 km, Figure 9 (c) and Figure 10 (c) respectively represent the spectral radiation under the condition of 81 km. From Figures 7-10 it can be seen that, whether the detection direction is the front direction or the side direction, the radiation intensity decreases with the increase of the height. At the same time, it is noticed that the high-temperature radiation region is mainly concentrated in the head stagnation zone, and the range is very small

[0196] Briefly, the modeling method for high-temperature flow field air spectrum radiation characteristics disclosed by the application mainly aims at unknown radiation sources in complex background, and proposes a high-temperature flow field air spectrum radiation characteristics modeling method considering accuracy and efficiency in different detection directions and detection wave bands. The implementation process is as follows: reconstructing non-equilibrium spectral parameters to obtain accurate gas radiation characteristic parameters; establishing a high-temperature flow field non-equilibrium gas radiation characteristic parameter database; analyzing the influence of flow field gradient distribution, selecting efficient and reliable flow field gradients, and calculating the radiation transmission exit intensity by using the LOS method; and expanding the spatial multi-point source calculation to obtain the air spectrum radiation characteristics of the high-temperature flow field in different spectral intervals. The high-temperature flow field air spectrum radiation characteristics solving method established by the application provides an effective basis for target detection and identification.

[0197] The embodiments of the present disclosure also provide a high-temperature flow field air spectrum radiation characteristics system, comprising:

[0198] The first processing unit is configured to:

[0199] determine a non-standard state line function by using a Voigt line type based on non-equilibrium gas radiation characteristic parameters and according to the principle that Doppler broadening and Lorentz broadening are independent of each other, and obtain superimposed absorption coefficients and emission coefficients based on the non-standard state line function;

[0200] The second processing unit is configured to:

[0201] obtain radiation intensities transmitted under different flow field gradients based on the absorption coefficients and emission coefficients, analyze the result error of the radiation intensities transmitted under different flow field gradients, and determine the flow field gradient required for radiation intensity calculation;

[0202] The third processing unit is configured to:

[0203] obtain the radiation exit intensity of a single point source by using the LOS method based on the flow field gradient, absorption coefficients and emission coefficients;

[0204] The fourth processing unit is configured to:

[0205] slice the flow field according to the transmission direction in the field, and calculate the radiation exit intensity of each slice in the detection direction by using the LOS method and the flow field gradient;

[0206] The output unit is configured to:

[0207] determine the detection direction and detection wave band of the target high-temperature flow field, determine the atmospheric transmission transmittance at the flight height according to the flight height and atmospheric transmission distance, perform attenuation calculation on the radiation exit intensity, and obtain the spatial and spectral distribution characteristics of the radiation intensity of the target high-temperature flow field in the corresponding spectral interval.

[0208] In another embodiment of the present application, a computer device is provided, which comprises a processor and a memory, the memory is configured to store a computer program, the computer program comprises program instructions, and the processor is configured to execute the program instructions stored in the computer storage medium. The processor can be a central processing unit (CPU), and can also be other general-purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc., which are the computing core and control core of the terminal, and are suitable for implementing one or more instructions, and are particularly suitable for loading and executing one or more instructions in the computer storage medium to implement a corresponding method process or a corresponding function; the processor in the embodiments of the present application can be used for the operation of the method for the high-temperature flow field air spectrum radiation characteristic.

[0209] In another embodiment of the present application, the present application further provides a storage medium, specifically a computer readable storage medium (Memory), which is a memory device in a computer device, and is configured to store programs and data. It can be understood that the computer readable storage medium herein can include an internal storage medium in the computer device, and of course can also include an expansion storage medium supported by the computer device. The computer readable storage medium provides a storage space, and the storage space stores an operating system of the terminal. In addition, one or more instructions suitable for being loaded and executed by the processor are also stored in the storage space, and the instructions can be one or more computer programs (including program codes). It should be noted that the computer readable storage medium herein can be a high-speed RAM memory, or a non-volatile memory such as at least one disk memory. One or more instructions stored in the computer readable storage medium can be loaded and executed by the processor to implement the corresponding steps of the method for the high-temperature flow field air spectrum radiation characteristic in the above embodiments.

[0210] Those skilled in the art will appreciate that embodiments of the present application can be readily used as a method, a system or a computer program product. Accordingly, the present application can take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application can take the form of a computer program product on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROMs, optical storage devices, etc.) embodying computer readable program code.

[0211] The present application is described in reference to the flowchart illustrations and / or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general purpose computer, special purpose computer, embedded processor or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart illustrations and / or block diagrams block or blocks. Figure 1 one or more functions specified in the flowchart illustrations and / or block diagrams block or blocks. Figure 1 one or more functions specified in the flowchart illustrations and / or block diagrams block or blocks.

[0212] These computer program instructions can also be stored in a computer- readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instructions which implement the function specified in the flowchart illustrations and / or block diagrams block or blocks. Figure 1 one or more functions specified in the flowchart illustrations and / or block diagrams block or blocks. Figure 1 one or more functions specified in the flowchart illustrations and / or block diagrams block or blocks.

[0213] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart illustrations and / or block diagrams block or blocks. Figure 1 one or more functions specified in the flowchart illustrations and / or block diagrams block or blocks. Figure 1 one or more functions specified in the flowchart illustrations and / or block diagrams block or blocks.

[0214] The foregoing merely illustrates the principles of the application and application of its leading features. This application is not limited to the exact details shown above and described herein, and obvious modifications will occur to those skilled in the art upon reading the foregoing description. Therefore, the scope of the application is not to be determined by the specific examples shown above, but only by the claims below. Any reference signs in the claims should not be construed as limiting the scope of the claims.

[0215] Furthermore, it should be understood that although the description above relates to embodiments, not every embodiment contains only one independent technical solution, and the description above is only for the sake of clarity, and those skilled in the art should understand the description as a whole, and the technical solutions in each embodiment can be appropriately combined to form other embodiments that those skilled in the art can understand. The above is only to illustrate the technical idea of the present application, and cannot limit the protection scope of the present application. Any modification made on the basis of the technical idea of the present application, which is within the scope of the technical solutions, falls within the protection scope of the claims of the present application.

Claims

1. A method for determining the spatial spectrum radiation characteristics of a high-temperature flow field, characterized in that: The following steps are involved: Based on the radiation characteristic parameters of the non-equilibrium gas and the principle that Doppler broadening and Lorentz broadening are independent of each other, the Voigt line shape is used to determine the linear function under the non-standard state, and the superimposed absorption coefficient and emission coefficient are obtained based on the linear function under the non-standard state; Obtaining the radiation intensity transmitted under different flow field gradients based on the absorption coefficient and the emission coefficient, analyzing the result errors of the radiation intensity transmitted under different flow field gradients, and determining the flow field gradient required for the radiation intensity calculation; The radiation emission intensity of the single point source is obtained by using the LOS method based on the flow field gradient, absorption coefficient and emission coefficient; Slicing the flow field according to the transmission direction within the field, and calculating the radiation emission intensity of each slice in the detection direction using the LOS method and the flow field gradient; Determine the detection direction and detection band of the target high-temperature flow field, determine the atmospheric transmission transmittance at the flight altitude based on the flight altitude and atmospheric transmission distance, perform attenuation calculation on the radiation emission intensity, and obtain the spatial and spectral distribution characteristics of the radiation intensity of the target high-temperature flow field in the corresponding spectral interval; According to the principle that Doppler broadening and Lorentz broadening are independent of each other, the Voigt line shape is used to determine the linear function under the non-standard state, and the process of obtaining the superimposed absorption coefficient and emission coefficient based on the linear function under the non-standard state is as follows: The central wave number is calculated as The spectrum line is at wave number The broadening line function : According to the independent characteristics of Doppler broadening and Lorentz broadening, the Voigt line shape function is calculated by approximating the broadening line shape function. , the expression is as follows: Where, 、 、 are the half-width of the spectral line of Lorentz broadening, Doppler broadening and Voigt line type respectively; Calculate the absorption and emission coefficients of a non-equilibrium gas in the bound-bound, bound-free, and free-free transition mechanisms respectively: Where, is the transition wave number, ; is the Einstein spontaneous transition coefficient, ; and are the degeneracy of high and low energy levels, respectively; and is the gas particle population at high and low energy levels, ; is the spectral line shape function; is the total number of atoms; is the atomic partition function; is the mass of the electron, is the degeneracy of energy level k, refers to the total absorption cross section at energy level k, is the Gaunt factor, and its expression is , Z is the atomic number, and are the densities of electrons and ions, respectively.

2. The method for determining the spatial spectrum radiation characteristics of a high-temperature flow field according to claim 1, characterized in that: Preprocessing the non-equilibrium gas radiation characteristic parameters includes the following steps: Calculating spectral line intensities under non-standard conditions :For temperature T and pressure P, the spectrum line has wave number Strength at Expressed as: Where, P 0 is the pressure under standard conditions; T 0 is temperature; is the electron-vibration temperature; h is Planck's constant; c is the speed of light; k is the Boltzmann constant; is the actual total pressure of the gas; is the line strength under standard conditions; is the wave number; is the number of molecules per unit volume under standard conditions; is the total partition function at two temperatures; is the transition low state energy; Calculate the translational-rotational temperature of a molecule and electron-vibration temperature The partition function is expressed as follows: Where, is the electronic energy level of the molecule; is the vibrational energy level of the molecule; is the rotational energy level of the molecule; For electronic state n , v = 0 corresponding vibration energy; is the symmetry factor, for heteronuclear molecules = 1, homonuclear molecule = 2; is the statistical weight of the electron energy level; is the degeneracy of the rotational energy levels; The number density of nonequilibrium gas molecules at the translational-rotational temperature and electron-vibration temperature The calculation expression is as follows: Vibration energy value , rotational energy value F Calculation, unit (cm-1): Where, is the electronic statistical weight; , is the degeneracy of the low energy level; is the rotational quantum number of the low energy level; , , They are the electronic energy term, vibration and rotation energy term values ​​respectively, and the unit is J.

3. The method for determining the spatial spectrum radiation characteristics of a high-temperature flow field according to claim 1, characterized in that: Analyzing the error in the radiation intensity results under different flow field gradients includes the following steps: Calculate the non-equilibrium gas radiation physical parameters corresponding to different gradient distributions, and calculate the total absorption coefficient and emission coefficient after superposition: Where, is the central wave number of the i-th spectral line; Si is the central wave number of the i-th spectral line The strength of the place; is the line broadening function; The high-temperature flow field shock layer is divided into 9 facets, different gradient distributions are set, and the LOS method is used to calculate the radiation emission intensity of each facet: The calculation time of each gradient is recorded and the calculation accuracy of the radiation intensity under each gradient is analyzed. Under the premise of ensuring the accuracy and reliability of the calculation results, the best smooth gradient distribution is selected; Where, Indicates the directional spectral radiation intensity of the nth layer; Indicates the transmittance of the nth layer of medium; L is the path length of light transmitted in the nth layer of medium, and in the non-equilibrium state, Emission coefficient replace.

4. The method for determining the spatial spectrum radiation characteristics of a high-temperature flow field according to claim 1, characterized in that: The process of obtaining the radiation emission intensity of a single point source is as follows: Take the environmental variable Data in the flow field: divide the flow field medium on the transmission path into 10 layers, each layer is regarded as an isothermal and uniform medium, and take the mean value of the flow field parameters of each layer, Data1-Data10; Starting from the flow field thickness, the spectral radiation emission intensity of a single point source in the shock layer is solved by the LOS method based on the mean value of the flow field parameters Data1-Data10 of each layer: Where, is the directional spectral radiation intensity of the nth layer; Indicates the transmittance of the nth layer of medium; is the emission coefficient.

5. The method for determining the spatial spectrum radiation characteristics of a high-temperature flow field according to claim 1, characterized in that: The process of calculating the radiation emission intensity of each slice in the detection direction is: According to the propagation direction of radiation in space, the entire flow field is precisely geometrically divided into a series of slices, each of which has a clear boundary in space and can represent the local characteristics of the flow field in that direction; On each of the slices, a series of coordinate points are defined, which will be used to calculate the radiation emission intensity, and the coordinate points uniformly cover the entire slice area; The LOS method is used to solve the radiation transfer equation and calculate the radiation emission intensity of the coordinate point on each slice. At the same time, the position of the coordinate point and the calculated corresponding radiation intensity value are stored.

6. The method for determining the spatial spectrum radiation characteristics of a high-temperature flow field according to claim 1, characterized in that: The process of obtaining the spatial and spectral distribution characteristics of the radiation intensity of the target high-temperature flow field in the corresponding spectral interval is as follows: Determining a detection direction and a detection band. The detection direction determines the viewing angle of radiation calculation. The selection of the detection band involves the spectral resolution of the radiation and determines the type and characteristics of the detected radiation. According to the flight altitude, the atmospheric transmission distance is set, the atmospheric transmission transmittance is calculated using the radiation transmission model MODTRAN, and the atmospheric transmission transmittance is used to perform attenuation calculation on the radiation emission intensity at all the slice points; According to the spatial and spectral distribution characteristics of the radiation intensity of the target high-temperature flow field in the corresponding spectral interval, the spatial-spectral radiation characteristics of the target high-temperature flow field are modeled, and the spatial and spectral distribution characteristics of the radiation intensity of the target high-temperature flow field in the corresponding spectral interval are obtained based on the modeling of the spatial-spectral radiation characteristics.

7. A system for measuring the spatial spectrum radiation characteristics of a high-temperature flow field, characterized in that: The method based on the high-temperature flow field spatial spectrum radiation characteristics according to any one of claims 1 to 6 comprises: The first processing unit is configured to: Based on the radiation characteristic parameters of the non-equilibrium gas and the principle that Doppler broadening and Lorentz broadening are independent of each other, a Voigt line shape is used to determine a linear function under a non-standard state, and based on the linear function under the non-standard state, a superimposed absorption coefficient and emission coefficient are obtained; The second processing unit is configured to: Used to obtain the radiation intensity transmitted under different flow field gradients based on the absorption coefficient and the emission coefficient, analyze the result error of the radiation intensity transmitted under different flow field gradients, and determine the flow field gradient required for radiation intensity calculation; The third processing unit is configured to: Used to obtain the radiation emission intensity of a single point source using the LOS method based on the flow field gradient, absorption coefficient and emission coefficient; The fourth processing unit is configured to: Used to slice the flow field according to the transmission direction within the field, and calculate the radiation emission intensity of each slice in the detection direction using the LOS method and the flow field gradient; Output unit, configured as: It is used to determine the detection direction and detection band of the target high-temperature flow field, determine the atmospheric transmission transmittance at the flight altitude according to the flight altitude and atmospheric transmission distance, perform attenuation calculation on the radiation emission intensity, and obtain the spatial and spectral distribution characteristics of the radiation intensity of the target high-temperature flow field in the corresponding spectral interval.

8. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the steps of the method for high-temperature flow field spatial spectrum radiation characteristics as described in any one of claims 1 to 6 are implemented.

9. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the method for high-temperature flow field spatial spectrum radiation characteristics are implemented as described in any one of claims 1 to 6.

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