Flow And Heat Transfer Analysis Of Supersonic Boundary Layer

Hypersonic technology plays an important role in consolidating national defense security.Major powers in the world are increasing investment in developing hypersonic flight with faster flight speed,shorter response time and stronger penetration ability.However,the research and development of hypersonic aircraft is facing great challenges.The external air flow is compressed violently and rubs violently with the aircraft skin,resulting in strong aerodynamic heating of the aircraft.Sudden aerodynamic heating will produce a lot of aerodynamic heat,which makes the aircraft skin produce strong thermal stress,thermal strain and material corrosion,and worsen the working environment in the cabin.Therefore,the research on the heat and momentum transfer of aircraft in flight plays an important role.This paper discusses the flow and heat transfer analysis of hypersonic boundary layer with gas injection and the unsteady flow and heat transfer law of hypersonic glider laminar boundary layer.The contents of the study are as follows:1)Gas injection is an important way to reduce the aerodynamic heat of hypersonic aircrafts.In this paper,the analytical method is used to study the laminar boundary layer flow and heat transfer characteristics of compressible fluid on permeable wall with uniform gas injection.Based on the similarity principle of momentum transfer,energy transfer and mass diffusion,it is assumed that the viscosity coefficient,thermal conductivity and diffusion coefficient are nonlinear power functions of temperature.Therefore,the hypersonic nonlinear boundary layer governing equations are established.The partial differential governing equation is transformed into ordinary differential governing equation by Illingworth similarity transformation,and solved by homotopy analysis(HAM).The influence of gas injection intensity on flow and heat transfer is revealed.With the increase of gas injection intensity,the wall temperature decreases significantly;The larger the incoming Mach number,the higher the wall temperature.when the free flow Mach number is 5Ma,the leading edge shear force of the plate exceeds 3000 N.2)Based on the shape characteristics of hypersonic glider,the unsteady flow and heat transfer law of hypersonic glider boundary layer are studied.Based on Sutherland formula,it is assumed that viscosity and thermal conductivity are functions of temperature.Based on the hypersonic boundary layer theory,the governing equations of unsteady flow and heat transfer in hypersonic laminar boundary layer are established.The partial differential equations are dimensionless and solved by the finite difference method.The effects of key parameters on the laminar boundary layer flow and heat transfer of hypersonic glider are revealed.The theoretical model constructed in this paper can lay a theoretical foundation for the further study of aircraft outflow field.By comparing with the results in the literature,the effectiveness of the solution method is verified.The influence of various parameters on the heat and momentum transfer of the aircraft and the calculated shear force can provide relevant theoretical basis for the material selection of hypersonic aircraft.