Investigation On Characteristics Of Transpiration Cooling For Hypersonic Vehicle Leading Edge

This paper takes the leading edge of hypersonic vehicle as the research object,combines with film cooling on the basis of transpiration cooling,and verifies the effect of film-transpiration combined cooling.A comprehensive numerical model is used to analyze the influence of main factors on the leading edge combined cooling structure,which provides a reference for the application of the leading edge film-transpiration combined cooling structure.The main work are as follows:Firstly,the cooling effects of film cooling,transpiration cooling and combination cooling of hypersonic vehicle leading edge are compared.The results show that the leading edge film-transpiration combined cooling structure has the least consumption of coolant and the best cooling effect among the three.Secondly,under the condition of constant mass flow rate and constant velocity,the cooling effect of combined cooling structure with different coolants was studied.The results show that when the mass flow rate of the coolant is constant,the effect of low-density H₂ and He coolants is better.Then,the influence of attack angles of 0°,4°and 12°on the combined cooling effect was studied,and the influence of changing wedge angle on the combined cooling effect under symmetric and asymmetric leading edge configurations was studied respectively.The results show that the attack angle increases the temperature difference between the upper and lower half of the leading edge model.The maximum temperature difference between the upper and lower walls is 639.2 K.The change of attack angle affects the flow distribution of coolant in the structure by influencing the distribution of outside wall pressure.Increasing the upper wedge angle of the leading edge will reduce the distance of the coolant to the down-stream of the porous medium.There is an approximate linear growth trend of the outside wall temperature with the increase of the upper wedge angle.Finally,the cooling consumption of the combined cooling structure to achieve good cooling effect is studied when the flight Mach number and flight altitude are changed.The results show that when the flight altitude is30 km,the coolant mass flow rate of 0.005 kg/s can provide effective thermal protection for the leading edge model of this paper at the speed of Ma8 and below.When the flight Mach number is 6 and the flight altitude changes from 25 km to 40 km,0.005 kg/s of coolant mass flow rate can still meet the thermal protection requirements.