Numerical Simulation Of Interstage Aerothermodynamics Of Two-stage-to-orbit Vehicle

Two stage to orbit(TSTO)vehicle is an important vehicle scheme which can be used repeatedly and realize the round trip between the earth and the sky.This kind of vehicle can reduce the weight,improve the propulsion efficiency and reduce the launch cycle cost.However,when it flies in the atmosphere at high Mach number,it faces serious aerodynamic heating problems,especially the complicated shock wave interference between two stages of parallel two-stage to orbit vehicle has an important impact on the aerodynamic heating.At present,the international research mainly focuses on the aerothermal analysis of the two-stage to orbit vehicle which ignores the connection strut between stages and the simplified shape.In fact,the shape and strut of the vehicle will produce different aerothermal problems,which need to be further studied.Therefore,it is of great engineering significance to carry out the numerical simulation of aerodynamic heat between stages of two-stage to orbit vehicle.In this paper,the governing equations of aerothermal numerical simulation for two-stage to orbit vehicle are compressible Reynolds averaged Navier Stokes equations,which are solved by finite volume method.The second-order ausmdv scheme is used for space discretization,LU-SGS method is used for time discretization,and the two equation menter SST K scheme is used for turbulence simulation-ω Model.The accuracy of the numerical simulation method is verified by standard numerical examples such as M6 wing,hypersonic cylinder flow and double ellipsoid flow.In this paper,firstly,the numerical simulation of the aerodynamic heat of the twostage to orbit vehicle model without strut is carried out.Taking the two-stage to orbit vehicle model composed of wide velocity range vehicle and rocket as the research object,the aerodynamic heat of three reflected shock positions is mainly studied,and the shock interference and heat flow are classified.At the same time,the effect of angle of attack on the aerodynamic thermal environment of aircraft interstage is studied.The results show that there are two types of shock wave interference:one is reflected between two stages of two-stage to orbit vehicle,the other is not reflected between stages.The former increases the heat flux on the windward side and the upper surface of the rocket,while the latter interferes with the windward side of the wing,resulting in a V-shaped heat flux distribution.With the decrease of attack angle,the intensity of incident shock wave and reflected shock wave become weaker,the value of heat flux on the windward side of wide velocity range aircraft decreases,the range of the interference between shock wave and its wall becomes smaller,and the corresponding range of heat flux distribution decreases.In this paper,the aerothermal numerical simulation of the two-stage to orbit vehicle model with strut is carried out.The aerothermal environment of the windward side of the vehicle and rocket near the first strut and the second strut as well as the surface of the strut and the shock wave interference between stages are analyzed.Finally,the influence of strut on the aerodynamic heat of the two-stage to orbit vehicle model is studied by comparing with and without strut.The results show that the different types of shock wave/shock wave interference generated by the front and rear struts have different effects on the heat flow and boundary layer separation of the windward side of the wide velocity range vehicle,the upper surface of the rocket and the strut surface,and the influence of the strut on the aerodynamic heat of the two-stage to orbit vehicle can not be ignored.In this paper,the influence of strut configuration and position on the aerodynamic heat of the two-stage to orbit vehicle model is further studied.The heat flow,shock wave density gradient and boundary layer separation of the vehicle and rocket with wide velocity range near the front and rear struts are analyzed in detail.For different strut configurations,the laws of heat flow and shock wave density gradients in different directions are complex,and the boundary layer separation laws are as follows:for the windward side of wide velocity range vehicle near the front and rear struts and the upper surface of rocket near the second strut,the boundary layer separation region of NACA strut is the smallest,The absolute value of the minimum surface friction coefficient of diamond type is the smallest.For the upper surface of rocket near the first strut,the absolute value of the boundary layer separation region and the minimum surface friction coefficient of diamond strut are the smallest.Finally,the aerodynamic thermal effects of different rocket head configurations on the two-stage to orbit vehicle model are studied,and the heat flow,shock wave density gradient and boundary layer separation on the windward side of the vehicle and rocket near the front and rear struts are analyzed in detail.For different rocket head configurations,the density gradients of heat flow and shock wave in different directions of wide velocity range vehicle and rocket are complex,and the boundary layer separation rules are as follows:when the rocket head configuration is prototype,the absolute value of the boundary layer separation area and the minimum surface friction coefficient of the wide velocity range vehicle near the front and rear struts and the second strut near the upper surface of the rocket reach the minimum,And the boundary layer separation region on the upper surface of the rocket near the first rod reaches the minimum.When the rocket head is von Karman type,the absolute value of the minimum surface friction coefficient on the upper surface of the rocket near the first rod reaches the minimum...