Aerodynamic Heat Radiation Simulation Of Mars Atmosphere Hypersonic Flight

Mars exploration is one of the extraterrestrial probes widely concerned by various countries.The high temperature gas surrounding the Mars probe has a strong radiant heating effect on the wall surface during high-speed flight.It is of great significance to study the radiative heating effect under different flight conditions and to explore the distribution law of wall radiant heat flow for the design of next-generation Mars flight detector.In this paper,the Mars science laboratory（MSL）with/without angle of attack flight flow field is firstly simulated,then the simulated surface heat flow results are compared with the T5 wind tunnel test data.The numerical model and method are verified.Then the real flight conditions of the MSL are explored to obtain the Martian atmospheric profile and the MSL flight corridor.Based on this,the thermodynamic characteristics equilibrium and non-equilibrium of the two groups at different altitudes are numerically analyzed.The effects include the temperature and pressure distributions of the flow field,the Mach number,temperature,pressure on the stagnation line and the mole fraction distribution of each reaction component under the single-temperature and two-temperature models.In addition,the difference in flow field simulation results between 10 component 16 chemical reaction models and 8 component 8 chemical reaction models were studied.Due to the harsh flight environment of the Mars entry aircraft,the temperature of the shock layer gas is as high as several thousand Kelvin.Under such temperature conditions,the shock layer gas contributes greatly to the radiant heating of the aircraft wall.Currently,because of extremely time-consuming in calculating the radiation properties of gas,the LBL method is hardly popularized in engineering applications.In order to reduce the computational time cost,this article based on the high-resolution spectral database HITEMP-2010 and CDSD-4000,using LBL and narrow-band K distribution model,self-programming to achieve the code,and verify the correctness of the program,in addition,the effect of different narrowband widths on the absorption coefficient was compared.Finally,two CO₂ narrow-band K-distribution absorption coefficient databases（corresponding to HITEMP-2010 and CDSD-4000 database）and a CO narrowband absorption coefficient database（corresponding to the HITEMP-2010 database）build,which has a narrow-band width of 25cm^-1,a temperature range of 300K-10000 K,a total of 98 temperature points,and CO₂ and CO gas molar fractions range of 10^-6to 1,a total of 25 component ratios.To calculate the wall radiant heat flow,the code of radiation transmits called LOS has been programed and the correctness of the code has been verified.Finally,based on the flight flow result of the aircraft by numerical calculations and the database of CO₂ and CO narrow-band K-distribution absorption coefficient,the radiant heat flow of the CO₂ and CO gas in the flight flow field of the Mars entry aircraft to the heat-resistant wall of the aircraft has been calculated.The results show that the radiative heat flux distribution on the wall is characterized by high middle height and low nose and shoulders.The total radiant heat flux calculated at a height of 40 km is higher than that at 50 km,and the single-temperature model at 40 km has the largest calculation result,which is about 2.48 w/cm²,under this condition,the contribution of CO₂ to the surface radiant heat flux is greater than that of CO.