Numerical Study On Heat Transfer Characteristics Of Plate And Lip Structure With Transpration Cooling

With the rapid development of aerospace technology in recent years,hypersonic vehicles have become the focus of research in various countries around the world due to their huge military strategic significance.However,the intense aerodynamic heating during hypersonic flight poses a huge challenge to the material properties of the airframe structure.Compared with traditional cooling methods,transpiration cooling has the advantages of uniform cooling effect,good film coverage,high cooling efficiency,and easy control.It is gradually attracting the attention of researchers and considered to be the most promising cooling technology.This paper takes the thermal protection of aircraft surface as research background,establishes a numerical model of transpiration cooling,and use numerical simulation to conduct study on the heat transfer characteristics of porous media with transpiration cooling.First,use the porous media model in the Fluent software to construct a numerical model of transpiration cooling,use the LTE model to solve the heat transfer problem in the porous medium,and fit the physical properties of gaseous medium.Based on previous experiments and numerical simulations,the numerical model constructed in this paper was verified.Secondly,taking the porous medium plate as research object,the transpiration cooling phenomenon in high-temperature channel was studied.Considering the two methods of gas cooling and water cooling,numerical simulations are carried out on the transpiration cooling of porous media under different working conditions,and the influence of coolant types and porous media material properties on transpiration cooling is analyzed.The results show that the cooling effect of liquid water is better than gas cooling.In gas transpiration cooling,gas with larger specific heat capacity and smaller molecular mass can be selected as coolant.The thermal conductivity of porous media mainly affects the uniformity of the temperature field of transpiration cooling.The thickness of the porous medium mainly affects the injection pressure of the coolant.Finally,taking the GK-01 inlet as research object,Numerically simulated the environment that the model faces under real flight conditions,and explored the influence mechanism of flight speed and altitude on the heat flux on the inlet wall.Numerical simulation of transpiration cooling of lip was carried out with gas as coolant,the results show that the lip undergoes extremely uneven heat flux during hypersonic flight,the leading edge and the lower wall of the lip have high heat flux,and the upper wall has low heat flux.The heat flux of the lip wall increases parabolicly with the increase of Mach number,and decreases sharply with the increase of flying height.The wall heat flux decreases linearly with the increase of wall temperature.Useing transpiration cooling method can significantly reduce the temperature of the lip.However,due to the difference of thermal environment around the lip,the cooling effect varies greatly when uniform porosity is used.The non-uniform porosity setting can improve the cooling effect.