Study Of Aerodynamic Heating Environment On Blunt-Fin Gap Of Hypersonic Vehicle

With the development of hypersonic vehicle related technology,the performance demanding of vehicle is higher and higher,and aerodynamic configuration of vehicle has become complicated.In order to control the vehicle attitude,it needs to arrange different fin on the vehicle.There are complicated physical phenomena between air rudder and the fuselage,such as the shock boundary interaction,shock wave and shock wave interaction,separation and reattachment occur on the boundary layer etc.It's extremely serious aerodynamic heating in local blunt rudder.For the sake of changing the rudder deflection and containing the thermal expansion of the temperature rise of the structure,it usually reserve some gaps for installing the blunt rudder.Comparing with the blunt-fin without gap,the flow field structure and aerodynamic heating with the blunt-fin is more complicated.With the emergence of the gap,high-speed fluid of the upstream fin will crush into the gap.Then the gap vicinity surface will appear multiple the separation and reattachment lines and corresponding form the local high heat flux regions.Meanwhile,there will come into being vortexes in the gap inside,and it may have great changes with the heat-transfer characteristic of the gap.The radiative heat transfer of the gap is limited because of the relatively small gap structure.With the high-speed fluid crush into the gap,the convective heat transfer of the gap may strengthen remarkably.It may emerge high temperature in the vicinity of the gap surface and rudderpost,and it may induce serious ablation.So it's very significance to study the flow field characteristic and heat-flux distribution of the blunt-fin gap,and research the effects of blunt-fin gap aerodynamic heating with different geometrical parameters and free stream parameters.For instance,the United States have amount of the blunt-fin gap experiments before launching the X-37 B.The previous research mainly relies on the flight test and needs a lot of time and much money,so it may restrict the hypersonic vehicle development.In this case,by the independently developed procedure with our team,the aerodynamic heating of the blunt-fin gap with hypersonic vehicle is investigated in this paper.The thesis contains five sections.The first section gives introduction of the research background and meaning,the current research status and results with the blunt-fin aerodynamic heating in hypersonic vehicle are introduced briefly.In the second section,the numerical methods and a validation case about the blunt-fin without gap are presented.In the numerical methods part,the Navier-Stokes equations are solved by using the finite-volume solver.In the validation procedure part,the blunt-fin without gap is used for verifying through the flow field structure,pressure and heat-flux.Section three has analyzed the flow of the blunt-fin gap.At first,based on the blunt-fin without gap,the design process and grid generation for the blunt-fin gap model are presented.Then the flow field structure and heat flux distribution with the blunt-fin gap are introduced and explained in detail.The fourth section follows on the previous section,and investigation the effects of the geometrical parameters and free stream parameters to the flow field structure and heat flux distribution with the blunt-fin gap.With the gap height,the angle of attack and the Ma increasing,it gives the variation of the flow field structure and aerodynamic heating environment to the blunt-fin gap through the single variable method.These conclusions may contribute to the thermal-protection design with hypersonic vehicle.The fifth section is the conclusion.The summery and inadequacy of the research in this thesis and the outlook of the future work are presented.