Simulation Of Hypersonic Vehicle Using DSMC Method And Study Of Thermal Radiation

The severe interaction between hypersonic vehicle and gas leads to bow shock wave right in front of the vehicle. Due to the compression of shock wave, the temperature of air increase sharply while passing through shock layer. The internal energy of gas molecules is activated and comes with various chemical reaction such as dissociation, ionization and so on.The direct simulation Monte Carlo method can be used to simulate nonequlibrium flow of high temperature and high enthalpy. It simulate behaviors of molecules in microcosmic point of view and is a powerful and accurate tool to simulate gas flow hypersonic blunt vehicle in high altitude.This paper simulated the hypersonic flow field using DSMC method and radiation characteristics on the basis of the released relative studies. The main work is divided into two parts which are the calculation of hypersonic flowfield of RAM-CII re-entry procedure and the radiation characteristics suffered by vehicle surface from shock wave laver.(1) Simulation of thermochemical nonequlibrium flow field around hypersonic vehicle based on DSMC methodThis paper use variable hard sphere model, Larsen-Borgnakke inelastic collision model, CLL gas surface interaction model to simulate the reaction flow of RAM-CII experimental blunt cone model. The nonequilibrium parameter such as overall temperature, translational temperature, vibrational temperature and dimensionless pressure distribution feature along stagnation streamline are investigated.(2) Simulation of optical radiative characteristics and transition process of shock layer a flow field around RAM-CII vehicleThe RAM-CII vehicle flow field data on different flight during25-45km are obtained using FASTRAN. According to infrared radiation mechanisms of the shock layer and wake flow field, using line-by-line method and the LOS model,the spatial, spectral distribution characteristics of radiation intensity and radiance of the overall flow field in3.0-5.0micro spectral range are calculated. In addition, the transportation characteristic of infrared radiation from flow field was studied.