Numerical Investigation On Aerothermodynamic Characteristics Of Hypersonic Vehicle And Scheme Design Of Ground Equivalent Test

To accurately predict the thermal environment of hypersonic vehicles,many scholars are committed to the research of aerodynamic thermal characteristics of hypersonic vehicle,which provides important solutions for the design of thermal protection system.This paper is based on the precise thermal analysis method of hypersonic vehicle,transform the hypersonic aerodynamic thermal effect into a semi-decoupled aerodynamic convective heat transfer coefficient for the thermal analysis of the airframe,and finally realize the decoupling calculation of the airframe temperature field and the aerodynamic flow field.In addition,the ground equivalent test verification model of thermal analysis and infrared thermal image simulation of aircraft is established.The main work carried out in this paper is as follows:1.The geometric model of hypersonic vehicle is designed according to the parameterized modeling method,the fuselage is constructed by the mode line design method,and the shape of the key section of the body is controlled by the quadratic curve method.After determining the size of each parameter,rapid construction can be realized.For accurate prediction of aerodynamic thermal characteristic data,the outflow field of aircraft is structured grided.The grid scale of near-wall surface is determined by MFP criterion,which based on molecular motion theory.2.The calculation procedure was verified by the aerodynamic thermal experiment on the front edge of the cylinder.The results show that the shape of the shock wave at the front edge of the cylinder is consistent with the experiment.And the aerodynamic data are consistent with the experimental data.The rationality of using the MFP criterion as the theoretical basis for the grid division of aircraft model is also verified before the aerodynamic thermal numerical simulation of hypersonic vehicle.3.Firstly,the distribution of each physical quantity in the calculation results of hypersonic vehicle is analyzed,and then the influence factors of altitude on the surface adiabatic temperature of the aircraft are analyzed.Two kinds of flight states are selected,and the adiabatic temperature is calculated by aerodynamic thermal simulation.Then the radiative equilibrium temperature of the aircraft is obtained by setting the emissivity,and the convective heat transfer coefficient is extracted by the radiative balance method.Finally,the influence of emissivity on the heat transfer coefficient is investigated.4.The test principle is introduced in detail,and the equivalent test flow chart is determined.The design and selection of each component of the system are carried out,mainly including the design and simulation verification of the Laval nozzle.In order to ensure the test duration,the gas storage tank and air compressor are reasonably matched.In addition,the heater with suitable power is selected,and a stable section is also needed to stabilize the airflow.The aerodynamic thermal data are collected by infrared thermal imager.Finally,the model is designed and the material is selected,and the flow field and temperature field distribution of the sample are verified numerically.A set of feasible and effective schemes has been formed.