| Inflatable decelerators are attracting more and more attention from the aerospace industry because of their lighter weight,larger payload and better deceleration effect in thin atmosphere.It is of great significance for engineering design and application to effectively predict its aerodynamic performance and understand its aerodynamic characteristics during the whole deceleration process.Firstly,based on the method of flight mechanics,Newton-Euler method is applied to establish the motion equation of the decelerator and obtain the trajectory parameters of the reentry process.By solving the Kemp-Riddell formula and Lees’ formula,the heat flow value at the stationary point and the variation law of aerodynamic overload with height are obtained.Based on the environmental characteristics of the flight trajectory,the basin characteristics of the full trajectory are determined.Then,the numerical calculation methods for each basin are researched.In the high Mach number basin,the N-S equation with chemical source term is used.On this basis,slip boundary conditions are added to the slip flow field.The results of numerical examples verify the accuracy of the numerical method.The influence of thermochemical non-equilibrium gas model and complete gas model on aerodynamic load distribution on the surface of decelerator is compared.The influence of slip condition on the aerodynamic force/heat was researched.It is found that the drag coefficient and heat flow value calculated without slip condition are higher.Finally,the aerodynamic characteristics of subsonic,supersonic and hypersonic under typical working conditions were studied.The results show that the gas velocity is accelerated after passing through the shoulder of the decelerator,and there are obvious eddies in the tail area.The numerical results are in good agreement with the results of the empirical formula.The maximum aerodynamic load is mainly concentrated in the cone head.Under hypersonic,the position of the shoulder is obviously heated,and the drag coefficient remains around 1.36.The pitching moment coefficient decreases with the increase of the angle of attack.The results show that the inflatable decelerator has good deceleration performance,stability performance and aerodynamic force/heat characteristics.The research content of this paper provides some theoretical basis for the design of inflatable decelerator and its application in engineering. |
