Numerical Investigation Of Infrared Target Properties Of Hypersonic Aircraft In Near Space

Due to the priorities of high speed、long voyage and outstanding penetration ability,hypersonic vehicle is drawing more and more attention,and will be used extensively in military action in the future.For hypersonic vehicles in near space,the infrared radiation come from heat radiation of body and gas radiation of shock layer.It is important and meaningful to study the infrared target properties for the recognition、track and intercept of hypersonic vehicles.In this article,aerodynamic heat was calculated using the finite volume method.Choosing the Numerical format、the chemistry reaction model and the catalyze model,the study puts stress on the influence of the first floor grid height on the numerical calculation of aerodynamic heat.Based on the gridding rules of wall parameter reynolds number,ELECTRE model was chose to analysis the range of grid reynolds number for different body position.It is necessary to know the coefficient of spectrum when calculate the radiation transfer of radiation of the gas surrounding the vehicles.The H2O、CO2、NO molecule are the major infrared radiation source.Based on the rules of HITRAN/HITEMP spectrum data base,we complied the program to compute the spectrum absorption coefficient and emissive coefficient using the line-by-line method,then compared the results with the data we got from experiments,validated the correctness of the program.Base on aforementioned research contents,we chose the head of missile as geometry model to calculate and got the flow parameter and spectrum coefficient of shock layer gas.We designed the grid of detector mirror and the radiation field grid of mirror nodes.A high efficiency search method was developed correlating the flow field grid and radiation field grid,then use the interpolation formula to transmit the data from the flow grid nodes to radiation grid nodes.The radiant illumination on the detector mirror was obtained through solving the radiative transfer equation.The first study about grid can be foundation of grid design for complicated vehicle.The model which is used to calculate radiant illumination on the detector mirror of missile seeker can be references when choosing the material of seeker and working wave band.What is more,the compute method about gas radiation can be used on studying infrared radiation characteristics of engine exhaust plume and simultaneous measurement of gas temperature and concentration and searching vehicles etc,has long-term engineering application potential.