Catalytic And Non-equilibrium Ettects Of The Aerodynamic Heat For The Mars Entry Capsule

Mars is one of the eight planets in the solar system,and it is an Earth-like planet.Mars exploration can improve the level of national science and technology.The problem of hypersonic aerodynamic heating must to be solved for the development of deep space exploration,while the phenomenon of thermo-chemical non-equilibrium and wall catalysis is a very important issue in the field of aerodynamic heating.In order to simulate the aerodynamic thermal environment more accurately,it is necessary to develop and adopt a more accurate mathematical model.In order to compare the effects of the chemical reaction model and the wall catalytic condition on the simulation results,two-dimensional numerical simulations of Mars Pathfinder(MPF)are carried out by the CFD-FASTRAN software.Firstly,in this paper,the two dimensional axis mathematical model of thermo-chemical non-equilibrium flow in hypersonic is presented.The aerodynamic thermal environment in different temperature model of the RAM-C is simulated by the CFD-FASTRAN software,which the chemical reaction model of 5 components and the fully catalytic wall condition are considered.The simulation results match references well.While the temperature model affects the value of wall heat-flux by affects the term of convective heat transfer.Then,to compare the influences of the wall catalysis condition on the simulation results,numerical simulation of two dimensional aerodynamic thermal environment in three cases of MPF is developed,which the fully catalytic wall and non-catalytic wall are considered,and the gas model is the model of 8 component.The results indicate that the wall catalytic conditions influence the component diffusion term of heat flux by changing the distribution of the components.And then the maximum wall heat flux of fully-catalytic model is 50%higher than the value of non-catalytic wall when the thermo-chemical non-equilibrium phenomenon is significant.In addition,the wall condition does not affect the wall pressure distribution,the mach number distribution,the shock standoff distance and the temperature distribution.Finally,to compare the influences of the gas model on the simulation results,numerical simulation of two dimensional aerodynamic thermal environment in three cases of MPF is developed,which the 8 component gas model and 11 component gas model are considered and the wall condition is fully catalytic wall.The results indicate that when the thermo-chemical non-equilibrium phenomenon is significant,the gas model affects the temperature of the flow field and the wall heat flux to some extend,and the distribution of the main components is also affected by the gas model.