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CN-121977786-A - High enthalpy unbalanced flow field parameter measurement method and device

CN121977786ACN 121977786 ACN121977786 ACN 121977786ACN-121977786-A

Abstract

The embodiment of the specification provides a method and a device for measuring parameters of a high-enthalpy unbalanced flow field of atomic oxygen and atomic nitrogen absorption spectrum, wherein the method comprises the steps of generating the high-enthalpy flow field at an outlet of a high-enthalpy wind tunnel spray pipe, synchronously measuring the same flow field region to be measured of the high-enthalpy flow field by adopting a laser absorption spectrum measuring system arranged in an experimental section of the high-enthalpy wind tunnel, obtaining Gaussian half-widths and integral absorption rates of atomic nitrogen characteristic spectral lines, gaussian half-widths and integral absorption rates of atomic oxygen characteristic spectral lines, simultaneously obtaining effective absorption optical paths of laser passing through the high-enthalpy flow field and pressure of the high-enthalpy flow field, setting an initial iteration value of electron population temperature of the flow field, carrying out iterative calculation to convergence of temperature parameters by adopting a constructed iteration algorithm based on the initial iteration value, obtaining final electron population temperature, and respectively obtaining translational temperatures of atomic nitrogen and atomic oxygen according to the Gaussian half-widths of the atomic nitrogen characteristic spectral lines and the Gaussian half-widths of the atomic oxygen characteristic spectral lines.

Inventors

  • ZENG HUI
  • LI JING
  • YAN XIANXIANG
  • YANG GUOMING
  • ZHU XINGYING

Assignees

  • 中国航天空气动力技术研究院

Dates

Publication Date
20260505
Application Date
20260209

Claims (10)

  1. 1. The method for measuring the parameters of the high enthalpy unbalanced flow field of the atomic oxygen and atomic nitrogen absorption spectrum is characterized by comprising the following steps of: Generating a high-enthalpy flow field at the outlet of the high-enthalpy wind tunnel jet pipe, synchronously measuring the same flow field region to be measured of the high-enthalpy flow field by adopting a laser absorption spectrum measuring system arranged in the high-enthalpy wind tunnel experimental section, obtaining Gaussian half-width and integral absorptivity of atomic nitrogen characteristic spectral lines and Gaussian half-width and integral absorptivity of atomic oxygen characteristic spectral lines, and simultaneously obtaining effective absorption optical path of laser passing through the high-enthalpy flow field and pressure of the high-enthalpy flow field; Setting an initial iteration value of the electronic population temperature of the flow field, and carrying out iterative calculation by adopting a constructed iteration algorithm until the temperature parameter converges based on the initial iteration value to obtain a final electronic population temperature; And respectively obtaining the translation temperature of the atomic nitrogen and the atomic oxygen according to the Gaussian half-width of the atomic nitrogen characteristic spectral line and the Gaussian half-width of the atomic oxygen characteristic spectral line.
  2. 2. The method of claim 1, wherein setting an initial iteration value of the electronic population temperature of the flow field, performing iterative computation with a constructed iterative algorithm based on the initial iteration value until the temperature parameter converges, and obtaining a final electronic population temperature specifically comprises: step 1, electronic population temperature based on current kth iteration Thermodynamic equilibrium and spectrum calculation are carried out to obtain atomic nitrogen and atomic oxygen at the temperature Line strength under And ; Step 2, based on the obtained line strength And The current absolute particle number density is calculated according to equation 1: equation 1; Wherein, the The integrated absorbance of the characteristic spectral line for atomic nitrogen, The integrated absorptivity of atomic oxygen characteristic spectral line is that L represents the effective absorption optical path of laser passing through high enthalpy flow field, Representing the current absolute particle number density of atomic nitrogen, Represents the current absolute particle number density of atomic oxygen; Step 3, calculating the atomic number density ratio based on the spectrum measurement currently according to a formula 2 according to the calculated absolute particle number density: equation 2; step4, utilizing a pre-established thermal chemical correlation function of the air component Wherein T represents flow field temperature and P represents flow field pressure, the flow field pressure P is obtained by measuring through a wind tunnel wall surface pressure sensor or a pitot tube or calculating according to wind tunnel operation total pressure parameters and nozzle expansion ratio, and under the condition of known pressure P, the atomic number density ratio which can be generated is found to be equal to The corresponding temperature of (2) is taken as the next iteration temperature I.e. solving equations , wherein, Representing the current absolute particle number density of atomic nitrogen to the absolute particle number density of atomic oxygen for the kth iteration; Step 5, calculating temperature iteration residual errors If (1) If the convergence rate is smaller than the preset convergence threshold value, stopping iteration and The final measured population temperature Otherwise, let Returning to the step 1, wherein the value interval of the preset convergence threshold is [1,10]; step 6, based on the final converged population temperature Executing the formula 1 in the step 2 again, calculating and outputting the absolute particle number density of the atomic nitrogen in the flow field And absolute particle number density of atomic oxygen 。
  3. 3. The method of claim 2, wherein the air component thermochemical correlation function The method comprises the specific steps of calculating to obtain the relation between the component concentration and the flow field temperature T and the flow field pressure P by adopting a minimum Gibbs free energy method.
  4. 4. The method of claim 2, wherein solving the equation The method specifically comprises the following steps: solving the equation according to equation 3 : Equation 3; Wherein, the To meet the requirements of Is used for the temperature control of the liquid crystal display device, Is a relaxation factor with a value range of 。
  5. 5. The method of claim 1, wherein setting an initial iteration value of the flow field electron population temperature specifically comprises: Setting an initial iteration value of the electron population temperature of the flow field according to the formula 4 : Equation 4; wherein P represents the pressure of the high enthalpy flow field, The integrated absorbance of the characteristic spectral line for atomic nitrogen, Is the integrated absorbance of atomic oxygen characteristic lines.
  6. 6. The method according to claim 1, wherein the obtaining of the translational temperatures of the atomic nitrogen and the atomic oxygen based on the gaussian half-width of the atomic nitrogen characteristic line and the gaussian half-width of the atomic oxygen characteristic line, respectively, comprises: the translational temperature T tr of atomic nitrogen and atomic oxygen is calculated according to equation 5: Equation 5; Wherein, the Is a half width of a gaussian shape, Is the center frequency and M is the molar mass.
  7. 7. The method of claim 1, wherein the atomic nitrogen characteristic line is selected from transition lines within a predetermined range of the 868nm band and the atomic oxygen characteristic line is selected from transition lines within a predetermined range of the 777nm band.
  8. 8. A device for measuring parameters of a high enthalpy unbalanced flow field of atomic oxygen and atomic nitrogen absorption spectrum, which is characterized by comprising: The acquisition module is used for generating a high-enthalpy flow field at the outlet of the high-enthalpy wind tunnel jet pipe, synchronously measuring the same flow field region to be measured of the high-enthalpy flow field by adopting a laser absorption spectrum measurement system arranged in the high-enthalpy wind tunnel experimental section, acquiring Gaussian half-width and integral absorption rate of atomic nitrogen characteristic spectral lines and Gaussian half-width and integral absorption rate of atomic oxygen characteristic spectral lines, and simultaneously acquiring effective absorption optical path of laser passing through the high-enthalpy flow field and pressure of the high-enthalpy flow field; the iteration module is used for setting an initial iteration value of the electronic population temperature of the flow field, and carrying out iterative calculation until the temperature parameter converges by adopting a constructed iteration algorithm based on the initial iteration value to obtain a final electronic population temperature; And the calculation module is used for respectively obtaining the translation temperatures of the atomic nitrogen and the atomic oxygen according to the Gaussian half-width of the atomic nitrogen characteristic spectral line and the Gaussian half-width of the atomic oxygen characteristic spectral line.
  9. 9. An electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, the computer program when executed by the processor performing the steps of the method for measuring high enthalpy unbalanced flow field parameters of atomic oxygen and atomic nitrogen absorption spectra according to any one of claims 1 to 7.
  10. 10. A computer-readable storage medium, wherein a program for realizing information transfer is stored on the computer-readable storage medium, and when the program is executed by a processor, the steps of the method for measuring the high enthalpy unbalanced flow field parameter of the atomic oxygen and atomic nitrogen absorption spectrum according to any one of claims 1 to 7 are realized.

Description

High enthalpy unbalanced flow field parameter measurement method and device Technical Field The document relates to the technical field of aerodynamic heat tests and measurement research of aircraft ground, in particular to a method and a device for measuring high-enthalpy unbalanced flow field parameters of atomic oxygen and atomic nitrogen absorption spectra. Background The high enthalpy wind tunnel represented by an arc wind tunnel, a high frequency induction wind tunnel and a pulse shock wind tunnel is main equipment for performing hypersonic aircraft thermal protection test assessment/thermal environment assessment. In the process of re-entering the air layer of the hypersonic aircraft, the gas in the shock wave layer is subjected to severe pneumatic heating, and complex thermochemical reactions such as dissociation and ionization are generated to form a high-temperature unbalanced flow field, so that the concentration and the temperature (translational temperature and electron population temperature) of key components (such as atomic nitrogen N and atomic oxygen O) in the flow field are accurately measured, and the method has a vital effect on verifying a aerodynamic thermodynamic model and evaluating the performance of a heat-resistant material. When measuring atomic components (N, O), the traditional "two-line thermometry" requires two spectral lines of different low energy levels and comparable absorption intensity to be selected for the same atom. However, in the near infrared band, it is difficult to find a diatomic line pair satisfying the conditions, and in order to measure the temperatures of N and O simultaneously, four lasers are often required, resulting in extremely complex optical systems and difficult alignment of optical paths. The existing single-line measurement method can only perform single-temperature measurement meeting the thermal balance assumption condition, has limited measurement applicability to unbalanced flow fields, and the measured temperature is often different from the thermodynamic unbalanced state of the flow fields, meanwhile, the particle number density obtained based on single-temperature measurement has huge deviation, and the innovative measurement method for accurately decoupling the temperature and the component concentration is required to be realized aiming at the characteristics of the high-enthalpy unbalanced flow fields. Disclosure of Invention The invention aims to provide a method and a device for measuring parameters of a high-enthalpy unbalanced flow field of atomic oxygen and atomic nitrogen absorption spectrum, and aims to solve the problems in the prior art. The invention provides a high enthalpy unbalanced flow field parameter measurement method of atomic oxygen and atomic nitrogen absorption spectrum, comprising the following steps: Generating a high-enthalpy flow field at the outlet of the high-enthalpy wind tunnel jet pipe, synchronously measuring the same flow field region to be measured of the high-enthalpy flow field by adopting a laser absorption spectrum measuring system arranged in the high-enthalpy wind tunnel experimental section, obtaining Gaussian half-width and integral absorptivity of atomic nitrogen characteristic spectral lines and Gaussian half-width and integral absorptivity of atomic oxygen characteristic spectral lines, and simultaneously obtaining effective absorption optical path of laser passing through the high-enthalpy flow field and pressure of the high-enthalpy flow field; Setting an initial iteration value of the electronic population temperature of the flow field, and carrying out iterative calculation by adopting a constructed iteration algorithm until the temperature parameter converges based on the initial iteration value to obtain a final electronic population temperature; And respectively obtaining the translation temperature of the atomic nitrogen and the atomic oxygen according to the Gaussian half-width of the atomic nitrogen characteristic spectral line and the Gaussian half-width of the atomic oxygen characteristic spectral line. The invention provides a high enthalpy unbalanced flow field parameter measuring device of atomic oxygen and atomic nitrogen absorption spectrum, comprising: The acquisition module is used for generating a high-enthalpy flow field at the outlet of the high-enthalpy wind tunnel jet pipe, synchronously measuring the same flow field region to be measured of the high-enthalpy flow field by adopting a laser absorption spectrum measurement system arranged in the high-enthalpy wind tunnel experimental section, acquiring Gaussian half-width and integral absorption rate of atomic nitrogen characteristic spectral lines and Gaussian half-width and integral absorption rate of atomic oxygen characteristic spectral lines, and simultaneously acquiring effective absorption optical path of laser passing through the high-enthalpy flow field and pressure of the high-enthalpy flow field; the iteration