Method, system, device and medium for measuring radiation characteristics of CN ultraviolet spectrum in non-equilibrium flow

Abstract

The application discloses a method, system, equipment and medium for measuring the radiation characteristics of CN ultraviolet spectrum in non-equilibrium flow, the method comprising the following steps: extracting the distribution data of temperature, pressure and component concentration in the flow field around a hypersonic aircraft along a determined line of sight direction; performing layered processing on the data; considering the influence of electronic reaction in a collision-radiation model according to the real flow field components, adding the transition process between excited states A and B, and solving the chemical reaction rates in the model; improving the calculation accuracy of the number density of CN (B) energy level and the calculation speed of the CN ultraviolet spectrum radiance in the flow field; and the system, equipment and medium are used for measuring the radiation characteristics of CN ultraviolet spectrum in non-equilibrium flow, the application adds the transition process between excited states A and B, and carefully solves the reverse rates of chemical reactions in the model, the description of the CN collision-radiation model is more accurate, the speed of solving the spectrum radiance is fast, and the accuracy is high.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of related calculation of molecular spectrum radiation, and particularly relates to a method, system, device and medium for measuring CN ultraviolet spectrum radiation characteristics in a non-equilibrium flow. BACKGROUND

[0002] At present, with the continuous development of aerospace industry, the accuracy and rapidity of high-speed vehicle detection are also constantly improving, and the research on the characteristics of high-speed vehicle body radiation has extremely important strategic and military significance. During the flight of the high-speed vehicle, an arc-shaped shock layer will be formed in the warhead part of the vehicle; in addition, the propellant burns and chemically reacts in the nozzle to produce a tail flame. There are vibration-rotation transitions of molecular atoms in the shock layer and the tail flame, which makes the flow field in a non-equilibrium state. In addition, carbon-based materials in the high-temperature flow field react with the surrounding atmosphere to produce CN free radicals, which have three obvious characteristic peaks in the ultraviolet and visible wave bands, and are one of the main radiation sources for vehicle detection and identification. Therefore, obtaining the accurate shock state energy level distribution of CN free radicals in the flow field has become the primary problem of studying the ultraviolet radiation of the vehicle body.

[0003] At present, the excitation state energy level distribution of CN free radicals is mainly solved by using a local thermodynamic equilibrium (LTE) model and a collision-radiation (C-R) model. In the LTE model, only the processes caused by heavy particle collisions between the ground state (X) and the second excited state (B) of CN and the molecular spontaneous radiation effects are considered. The C-R model adds the excitation reactions and recombination reactions induced by electrons and the recombination reactions caused by heavy particle collisions to the LTE model. Under the assumption of quasi-steady state, the main equations of the above two models can be expressed in matrix form according to the flow field components, temperature, pressure and other conditions, and the number density of CN excitation state energy levels can be obtained by solving the chemical reaction rate, molecular number density and other parameters in the matrix.

[0004] The existing model for solving the number density of non-equilibrium CN free radical energy levels (literature [1] Wright M, Olejniczak J, Walpot L, et al. A Code Calibration Study for Huygens Entry Aeroheating [C]. 44th AIAA Aerospace Sciences Meeting and Exhibit. 2006.

[0005] [2]Surzhikov S T.Radiative-collisional models in non-equilibriumaerothermodynamics of entry probes[J].Journal of Heat Transfer,2012,134(3):031002.1-031002.11.

[0006] [3]Brandis A M,Laux C O,Magin T,et al.Comparison of Titan EntryRadiation Shock-Tube Data with Collisional-Radiative Models[J].Journal ofThermophysics and Heat Transfer,2015,28(1):32-38.) have the following shortcomings: in LTE and C-R models, the influence of electrons in the flow field and the transition process between excited states A and B are ignored, thus simplifying the calculation process. Such simplification and assumption usually have large errors and analyze problems roughly, and cannot truly describe the layout of the energy level of the excited state of the molecule. In addition, the chemical reaction rate is an important parameter in LTE and C-R models, but the current processing of the chemical reaction rate in the model is mostly assumed to be equal to the forward and reverse rates. In summary, the simplification and assumption of the prior art usually have large errors and analyze problems roughly, and cannot truly describe the layout of the energy level of the excited state of the molecule. SUMMARY

[0007] In order to overcome the shortcomings of the prior art, the purpose of the present application is to provide a method, system, device and medium for measuring the radiation characteristics of CN ultraviolet spectrum in non-equilibrium flow, which considers the influence of electron reactions in the collision-radiation model according to the real flow field components, adds the transition process between excited states A and B, and solves the reverse rate of each chemical reaction in the model. Through the improvement of the model and the accurate solution of the chemical reaction rate, the calculation accuracy of the CN(B) energy level number density is improved, thereby significantly improving the accuracy of the calculation of the CN ultraviolet spectrum radiation luminance in the non-equilibrium flow field around the hypersonic vehicle, and providing a theoretical basis for the accurate detection of high-speed targets.

[0008] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0009] A method for measuring the radiation characteristics of CN ultraviolet spectrum in non-equilibrium flow, specifically comprising the following steps:

[0010] Step 1, extract the distribution data of temperature, pressure and component concentration in the flow field around the hypersonic vehicle along the determined line of sight direction;

[0011] Step 2, the line-of-sight direction data in step 1 is processed in layers to obtain temperature, pressure and component concentration data of each layer;

[0012] Step 3, the matrix form of the main equation under the quasi-steady state assumption is derived for the CN C-R model with increased electronic participation in the reaction;

[0013] Step 4, the chemical reaction rate in the CN C-R model matrix is calculated;

[0014] Step 5, the flow field data in step 2 and the chemical reaction rate in step 4 are substituted into the main equation matrix in step 3 to calculate the number density N of the CN(B) energy level;

[0015] Step 6, according to the apparent integration method, the CN spectral radiance along a determined line of sight in the flow field is calculated by programming.

[0016] The specific method of step 3 is:

[0017] 3.1) According to the real component distribution of the flow field, the influence of electrons is considered in the CN C-R model, that is, the electron-induced excitation / de-excitation reaction is added And the electron-induced recombination reaction Where, And The rate of excitation / de-excitation reaction and the rate of three-body recombination reaction induced by electron collision between energy levels i and j are represented by and, respectively;

[0018] 3.2) The matrix form corresponding to the CN C-R model main equation is given; under the assumption of quasi-steady state, the term in the main equation is equal to zero, then the corresponding matrix form is:

[0019]

[0020] Where, n X , n A and n B are the number densities of CN molecules in the ground state, the first excited state and the second excited state, respectively. The energy level layout of CN in the ground state (X), the excited state (A and B) is considered, that is, the values of i and j are 1, 2, 3;

[0021] 3.3) The detailed calculation expressions of the elements in matrix B and matrix A are derived:

[0022]

[0023]

[0024]

[0025]

[0026]

[0027]

[0028]

[0029] where K (i,j) (T) and K (c,i) (T) represent the rate of the excitation / de-excitation reaction and the rate of the three-body recombination reaction induced by heavy particle collision between energy level i and j, A(i ,j) represents the rate of the spontaneous emission reaction caused by the transition of the electron energy level of CN molecule from energy level i to energy level j with the emission of a photon, K (i,c) and are the inverse reaction rates of the three-body recombination reaction caused by heavy particle or electron collision.

[0030] The chemical reactions in the CN C-R model matrix described in step 4 include heavy particle / electron induced excitation reaction, heavy particle / electron induced recombination reaction and spontaneous emission reaction, wherein the absorption of the spontaneous emission reaction is too low, the inverse process of the spontaneous emission reaction can be considered to be non-existent, only the forward process needs to be considered, and the forward reaction rate of the spontaneous emission reaction is known.

[0031] The calculation of the chemical reaction rates in the CN C-R model matrix described in step 4 includes:

[0032] 4.1) The forward reaction rate of the heavy particle induced excitation reaction is known as K (i,j) (T), and the corresponding inverse reaction rate of the heavy particle induced excitation reaction can be calculated by using the formula , wherein the equilibrium constant T a represents the control temperature and represent the ro-vibrational partition function of CN molecule energy level i and energy level j, respectively; E CN(j-i) is the transition energy from energy level j to energy level i; the solving process of the inverse reaction rate of the electron induced excitation reaction is the same as that of the inverse reaction rate of the heavy particle induced excitation reaction;

[0033] 4.2) The inverse reaction rate of the heavy particle induced recombination reaction is known as K (i,c) (T), and the corresponding forward reaction rate of the heavy particle induced recombination reaction can be solved by using the formula , wherein the equilibrium constant ZM(T) = 10000 / T, the equilibrium constant The solution formula is applicable to the range of 500K-50000K; the forward reaction rate solving process of the electron-induced recombination reaction is the same as that of the heavy particle-induced recombination reaction.

[0034] The specific method of step 6 is as follows:

[0035] According to the data after the layering treatment of step 2, the apparent integral method is used to program and calculate the CN spectral radiance along the determined visual line in the flow field:

[0036] 6.1) Based on the line-by-line method and the HITRAN high-temperature molecular database, the line intensity at different temperatures is calculated Wherein Q(T) represents the partition function at temperature T, E" represents the low state energy of the transition, v represents the wave number, c2 represents the second radiation constant, and T0 represents the reference temperature; the energy level number density obtained in step 5 can be used to calculate the absorption coefficient of a single layer α=S·N·Φ, wherein Φ is a linear function, and the Voigt line type can obtain more accurate absorption coefficient;

[0037] 6.2) The absorption rate of each layer is calculated 1-e -α·l , l represents the thickness of a single layer; the transmittance e -α·l ;

[0038] 6.3) Selecting the blackbody radiation as the initial radiance I0, based on the apparent integral method The spectral radiance after passing through the entire path is calculated, wherein the optical thickness τ λ =κ sλ ·l, I bλ represents the blackbody radiation function; it should be noted that when calculating the radiance of the nth layer, the attenuation effect of the path of the previous n-1 layers is passed through, that is, the discrete form of the equation is

[0039] A system based on the above-mentioned method for measuring the characteristics of CN ultraviolet spectral radiation in non-equilibrium flow, the system comprises:

[0040] A gas parameter distribution module is configured to extract the temperature, pressure and component concentration distribution of the gas flow field of the high-speed aircraft flying at high altitude.

[0041] A flow field layering processing module is configured to layer the flow field along a determined visual line direction according to the flow field distribution to obtain the temperature, pressure and concentration distribution of each component of each layer.

[0042] A chemical reaction rate calculation module is configured to calculate the chemical reaction rate in the CN collision-radiation model.

[0043] A number density calculation module is configured to bring the flow field parameters and the chemical reaction rate into the collision-radiation model, and to calculate the number density of CN at different electronic energy levels by programming;

[0044] A spectral radiance calculation module is configured to calculate the spectral radiance of CN in the plume or shock layer by programming according to the apparent integration method.

[0045] An apparatus based on the above-mentioned method for measuring the ultraviolet spectral radiation characteristics of CN in non-equilibrium flow, the apparatus comprising:

[0046] A memory is configured to store a computer program;

[0047] A processor is configured to implement the method for measuring the ultraviolet spectral radiation characteristics of CN in non-equilibrium flow according to steps 1 to 6 when the computer program is executed.

[0048] A computer readable storage medium stores a computer program, and the computer program can implement the method for measuring the ultraviolet spectral radiation characteristics of CN in non-equilibrium flow according to steps 1 to 6 when the computer program is executed by a processor.

[0049] Compared with the prior art, the present application has the following advantages:

[0050] (1) In step 3 of the present application, the influence of electrons in the CN collision-radiation model is considered, the transition process between the first excited state A and the second excited state B is added, and the calculation formula of each element in the matrix corresponding to the main equation of the CN collision-radiation model under the quasi-steady state condition is derived, which makes the description of the CN collision-radiation model more accurate.

[0051] (2) In step 4 of the present application, the detailed calculation formula of the reverse rate of the heavy particle / electron-induced excitation reaction and the forward rate of the heavy particle / electron-induced recombination reaction is given, and the determination accuracy is improved by detailed solving of the forward and reverse reaction rates.

[0052] (3) In step 6 of the present application, the CN collision-radiation model is associated with the radiation transfer equation, and the specific formula and detailed calculation process for solving the high-resolution spectrum of CN radicals under non-equilibrium state are given, which has the advantages of short calculation time and accurate calculation result.

[0053] In summary, the present application provides an accurate spectral line prediction model, considers the influence of electrons in the flow field, adds the transition process between the excited states A and B, and carefully solves the reverse rates of the chemical reactions in the model, which makes the description of the CN collision-radiation model more accurate; the matrix equation of the collision-radiation model is calculated by programming, and the spectral radiance is solved based on the apparent integration method, which has the advantages of short calculation time and accurate calculation result, and has important significance for the research of target early warning, detection and identification. BRIEF DESCRIPTION OF DRAWINGS

[0054] Figure 1 Flow chart of the present application.

[0055] Figure 2 The flow field data obtained by selecting NASA shock tube test data as reference for the present application, wherein, Figure 2 (a) is the temperature distribution, Figure 2 (b) is the component number density distribution.

[0056] Figure 3 The CN energy level number density calculated by the C-R model and the local thermodynamic equilibrium model (LTE model) of the present application is compared with the NASA shock tube test data.

[0057] Figure 4 The CN radiance in the spectral range of 400-430 nm (Δv = -1) of the present application. DETAILED DESCRIPTION

[0058] The present application is further described in detail below in combination with the drawings and specific examples.

[0059] A method for measuring the CN ultraviolet spectral radiation characteristics in non-equilibrium flow, specifically comprising the following steps:

[0060] (1) Extracting the temperature, pressure and component concentration distribution data in the flow field around a hypersonic vehicle along a determined line-of-sight direction;

[0061] (2) Layering the line-of-sight direction data in step (1) and setting an appropriate layer number to ensure the calculation efficiency and accuracy, and obtaining the temperature, pressure and component concentration data of each layer;

[0062] (3) Deriving the matrix form of the master equation of the CN C-R model with increased electron participation reaction under the quasi-steady state assumption;

[0063] 3.1) Considering the influence of electrons in the CN C-R model according to the real component distribution in the flow field, i.e. adding the electron-induced excitation / de-excitation reaction and the electron-induced recombination reaction wherein and represent the rate of excitation / de-excitation reaction and the rate of three-body recombination reaction induced by electron collision between energy levels i and j, and the reaction rate is only related to temperature and is independent of pressure, concentration and other parameters;

[0064] 3.2) Giving the matrix form corresponding to the master equation of the CN C-R model. Under the quasi-steady state assumption, the term in the master equation is equal to zero, and the corresponding matrix form is:

[0065]

[0066] where n X , n A and n B are the number densities of the ground state, the first excited state and the second excited state of CN molecule, respectively. The present application considers the energy level layout of the ground state (X), the first excited state (A) and the second excited state (B) of CN, i.e. the values of i and j are 1, 2, 3;

[0067] 3.3) Detailed calculation expressions of each element in matrix B and matrix A are derived:

[0068]

[0069]

[0070]

[0071]

[0072]

[0073]

[0074]

[0075] where K (i,j) (T) and K (c,i) (T) represent the rates of the excitation / de-excitation reactions and the three-body recombination reactions induced by heavy particle collision between the energy levels i and j, respectively, A (i,j) represents the rate of the spontaneous emission reaction caused by the transition of the electron energy level of CN molecule from the energy level i to the energy level j with the emission of a photon, K (i,c) and are the inverse reaction rates of the three-body recombination reactions caused by heavy particle or electron collision.

[0076] (4) Calculation of the chemical reaction rates in the CN C-R model matrix (taking the reaction involving N2 as an example);

[0077] 4.1) The forward rate K (i,j) (T) of the excitation reaction induced by heavy particle can be obtained by consulting the literature, and the corresponding inverse reaction rate can be calculated by using the formula , where the equilibrium constant T a represents the control temperature and represent the ro-vibrational partition functions of the energy level i and the energy level j of CN molecule, respectively; E CN(j-i)Transition energy from level j to level i. The solution process of the reverse rate of the electron-induced excitation reaction is the same as above;

[0078] 4.2) The forward rate of the heavy particle-induced recombination reaction can be obtained by consulting the literature (i,c) (T), using the formula The corresponding forward reaction rate can be obtained, where the equilibrium constant ZM(T) = 10000 / T, the equilibrium constant The solution formula is applicable to the range of 500K-50000K. The solution process of the forward rate of the electron-induced recombination reaction is the same as above.

[0079] 4.3) Due to the very low absorption of the molecule, the influence on the excited state energy level layout is minimal, and the spontaneous emission only exists in the forward process, and the forward reaction rate can be obtained by consulting the literature.

[0080] (5) The flow field parameters in step (2) and the chemical reaction rate calculated in step (4) are brought into the main equation matrix of the CNC-R model in step (3), and the number density N of the CN(B) energy level can be calculated by programming. The NASA shock tube test data are selected as the reference, the test flow field data are shown in Figure 2 , and the calculation results of the CN excited state energy level number density are shown in Figure 3 ;

[0081] (6) According to the apparent integral method, the CN spectral radiance along a certain line of sight in the flow field is calculated by programming.

[0082] 6.1) Based on the line-by-line method and the HITRAN high-temperature molecular database, the line strength at different temperatures is calculated where Q(T) represents the partition function at temperature T, E" represents the low state energy of the transition, v represents the wave number, c2 represents the second radiation constant, and T0 represents the reference temperature 296K. The energy level number density obtained in step (5) can be used to calculate the absorption coefficient of a single layer α = S·N·Φ, where Φ is a line function, and the Voigt line function can obtain more accurate absorption coefficient;

[0083] 6.2) The absorption rate of each layer 1-e -α·l , l represents the thickness of a single layer; the transmittance e -α·l ;

[0084] 6.3) The initial radiance I0 of the blackbody radiation is selected as the target, and the spectral radiance after passing through the entire path is calculated based on the apparent integral method , where the optical thickness τ λ = κ sλ · l, I bλThe blackbody radiation function is denoted by Bv(T). It is noted that when calculating the radiance of the nth layer, the attenuation effect of the path of the previous n-1 layers is taken into account, i.e. the discrete form of the equation is Figure 4 The CN radiance in the spectral range of 400-430 nm (Δv = -1) is calculated and compared with the data of the Huygens reentry into Titan's atmosphere.

[0085] Example 1: Taking the NASA shock tube experiment as an example, the shock wave speed is 5150 m / s, the gas mixture ratio is 98% N2 and 2% CH4, the shock tube flow field simulation data are as shown in Figure 1 , the experimental flow field data are as shown in Figure 2 , and the heavy particles participating in the reaction considered are N2, N, H, C, NH, H2 and CH. The CN energy level number density is calculated by using the LTE model and the C-R model respectively, and compared with the experimental data, as shown in Figure 3 .

[0086] Example 2: Taking the Huygens reentry into Titan's atmosphere experiment as an example, the shock wave speed is 5112 m / s, the gas mixture ratio is 95% N2, 3% CH4 and 1% Ar, and the path flight angle is 65°. The heavy particles participating in the reaction considered are N2, N, H, C, NH, C2, Ar, H2 and CH. The CN(B) energy level number density is obtained by using the C-R model, and the CN radiance is solved by combining the apparent ray method, and compared with the experimental data, as shown in Figure 4 .

[0087] As can be seen from Figure 3 , at the position of 0-3 cm, the agreement of the CN(A) number density calculated by the C-R model with the experimental data is better than that of the LTE model, and the difference between the two results is small at the position of 3-5 cm. Compared with the NASA experimental data, the accuracy of the CN(B) number density calculated by the C-R model is obviously better than that of the LTE model. Therefore, it can be concluded that the influence of the electron pair on the CN(B) number density is greater, so when the temperature in the flow field is very high, the gas molecules are ionized to produce electrons, and at this time the influence of the electrons cannot be ignored when calculating the CN molecule viloet band system radiation. As can be seen from Figure 4 , the calculation results at the position of 0-10 cm of the shock wave are in good agreement with the experimental measurement data, and the calculation results at the position of 1 cm are about 2 orders of magnitude lower than the measured values, which is mainly caused by the difference between the number density results calculated at this position and the experimental values.

[0088] In summary, the present application provides an accurate spectral line prediction model, considering the influence of electrons in the flow field in the CN collision-radiation model, increasing the transition process between the first excited state (A) and the second excited state (B), calculating the refined energy level transition coupling reaction rate value, and more accurately describing the CN excited state energy level number density. In the application of programming calculation collision-radiation model matrix equation and subsequent apparent integral method based on solving spectral radiance has the significant advantages of short calculation time and accurate calculation result.

Claims

1. A method for determining the ultraviolet spectral radiation characteristics of CN in a non-equilibrium flow, characterized in that, Specifically, the following steps are included: Step 1: Extract the distribution data of temperature, pressure and component concentration in the flow field around the hypersonic vehicle along the determined line of sight; Step 2: Perform layered processing on the line-of-sight data from Step 1 to obtain temperature, pressure, and component concentration data for each layer; Step 3: Derive the matrix form of the master equation for the CNCR model with increased electron participation under the quasi-steady-state assumption; 3.1) Based on the actual component distribution of the flow field, the influence of electrons is considered in the CN CR model, i.e., electron-induced excitation / de-excitation reactions are added. and electron-induced complex reactions in, and These represent the rates of the excitation / de-excitation reaction and the three-body recombination reaction, respectively, resulting from electron collision-induced transitions between energy levels i and j. 3.2) Give the matrix form of the master equation of the CNCR model; under the assumption of quasi-steady state, in the master equation... If a term is always equal to zero, then the corresponding matrix form is: Where, n X n A and n B Given the number densities of the CN molecule in its ground state, first excited state, and second excited state, consider the energy level layout of the CN ground state (X) and excited states (A and B), i.e., the values ​​of i and j are 1, 2, and 3. 3.3) Derive the detailed calculation expressions for each element in matrix B and matrix A: Among them, K (i,j) (T) and K (c,i) (T) represent the rates of the excitation / de-excitation reactions and the three-body recombination reaction induced by heavy particle collisions between energy levels i and j, respectively. (i,j) K represents the rate of spontaneous emission caused by the electronic transition of a CN molecule from energy level i to energy level j, emitting a photon. (i,c) and The reverse reaction rate is the rate of the three-body recombination reaction caused by collisions of heavy particles or electrons. Step 4: Calculate the chemical reaction rates in the CNCR model matrix; the chemical reactions in the CNCR model matrix include heavy particle / electron-induced excited reactions, heavy particle / electron-induced recombination reactions, and spontaneous emission reactions. Since the absorption of spontaneous emission reactions is too low, it can be assumed that there is no reverse process in spontaneous emission reactions; only the forward process needs to be considered, and the forward reaction rate of spontaneous emission reactions is known. The calculation of the chemical reaction rates in the CNCR model matrix includes: 4.1) The forward reaction rate of the heavy particle-induced excited reaction is known to be K. (i,j) (T), using the formula Calculate the reverse reaction rate of the corresponding heavy particle-induced excited reaction, where the equilibrium constant is... T a Indicates temperature control and Let E represent the vibrational-rotational partition functions of energy levels i and j in the CN molecule, respectively; CN(j-i) The transition energy is denoted as . The solution process for the reverse reaction rate of an electron-induced excited reaction is the same as that for a heavy particle-induced excited reaction. 4.2) The reverse reaction rate of the heavy particle-induced recombination reaction is known to be K. (i,c) (T), using the formula Find the forward reaction rate of the corresponding heavy particle-induced recombination reaction, where the equilibrium constant is... ZM(T) = 10000 / T, equilibrium constant The applicable range of the solution formula is 500K-50000K; the solution process for the forward reaction rate of electron-induced recombination reaction is the same as that for the forward reaction rate of heavy particle-induced recombination reaction. Step 5: Substitute the flow field data from Step 2 and the chemical reaction rate from Step 4 into the master equation matrix from Step 3 to calculate the number density N of the CN(B) level. Step 6: Calculate the CN spectral radiance along a defined line of sight in the flow field using the apparent integral method.

2. The method for determining the ultraviolet spectral radiation characteristics of CN in a non-equilibrium flow according to claim 1, characterized in that, The specific method for step 6 is as follows: Based on the data after layering in step 2, the CN spectral radiance along a defined line of sight in the flow field is calculated using the apparent integration method: 6.1) Calculation of linear intensity at different temperatures based on the line-by-line method and the HITRAN high-temperature molecular database. Where Q(T) represents the partition function at temperature T, E″ represents the low-state energy of the transition, ν represents the wavenumber, c2 represents the second radiation constant, and T0 represents the reference temperature; the absorption coefficient α = S·N·Φ of the monolayer is calculated using the energy level number density obtained in step 5, where Φ is a linear function, and the Voigt linear function can obtain a more accurate absorption coefficient. 6.2) Calculate the absorption rate of each layer 1-e -α·l , l represents the thickness of a single layer; transmittance e -α·l ; 6.3) Blackbody radiation is selected as the initial radiance I0 of the target, based on the apparent integration method. Calculate the spectral radiance after traversing the entire path, where the optical thickness τ λ =κ sλ ·l,I bλ Let represent the blackbody radiation function; note that when calculating the radiance of the nth layer, it will be affected by the attenuation of the preceding n-1 layers, i.e., the discrete form of the equation is:

3. A system for determining the ultraviolet spectral radiation characteristics of CN in a non-equilibrium flow according to any one of claims 1 to 2, characterized in that, The system includes: The gas parameter distribution module is used to extract the distribution of temperature, pressure, and component concentration in the gas flow field of a high-speed aircraft flying at high altitudes. The flow field stratification module is used to stratify the flow field along a defined line of sight based on the flow field distribution, and obtain the temperature, pressure and concentration distribution of each component in each layer. The chemical reaction rate calculation module is used to calculate the chemical reaction rate in the CN collision-radiation model. The number density calculation module is used to input flow field parameters and chemical reaction rates into the collision-radiation model and programmatically calculate the number density of different electronic energy levels in CN. The spectral radiance calculation module is used to calculate the spectral radiance of CN in a non-equilibrium flow field using the apparent integration method and programming.

4. An apparatus for measuring the ultraviolet spectral radiation characteristics of CN in a non-equilibrium flow according to any one of claims 1 to 2, characterized in that, The device includes: Memory, used to store computer programs; A processor is used to execute the computer program to implement the method for measuring the ultraviolet spectral radiation characteristics of CN in non-equilibrium flow as described in steps 1 to 6.

5. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, enables the determination of the ultraviolet spectral radiation characteristics of CN in a non-equilibrium flow based on the method described in any one of claims 1 to 2.

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