Research Of Engineering Method And Numerical Computation On Aerodynamic Heating Over Projectiles’ Head At High Speed

The aerodynamic heating and temperature fields over projectiles’ head at high speed in different flight conditions were calculated by using the coupling between the engineering method and numerical computation.Firstly, the reduced model of the projectiles’ head was divided into three partitions:stagnation point,hemisphere and cone body. The heat flux of stagnation point was calculated by simplified and modified Lees formula. Then on the hemisphere it was deduced by the coupling of the spherical geometry relationship and Lees heat flow formula on blunt body. But the caculation of the cone body began from the similar solution of flat-plate flow. The solution was deduced to get Stanton number of the same Reynolds number. The St number would be substituted into calculation for the heat flux of cone body.At the same time, the unstructured grid of the model was ploted in Tecplot8.0and the program of2-dimensional stead-state heat conduction would be writed inside Fortran language. Meanwhile, all the formulas would be assigned to the head surface as the third boundary condition.There were three parts in this research of the paper:the influences of the boundary layer transitions and blunted wedge of the cowl for the aerodynamic heat, the high-temperature effects on prediction for the specific numerical. The transition that based on Batt criteria was calculated under4-9Ma. Meanwhile, the paper modellings two different dullness heads for the research about alter of the aerodynamic heat. At last, the air could be regarded calorically perfects gas and thermally perfect gas. The high-temperature effects on prediction for the specific numeric would be analysed. This specific heat ratio was obtained from fitting formula between thermodynamic parameter and temperature.The calculations indicate that:compared to laminar flow, the high-temperature area on the head would expand under turbulence; The transition starting point woud antedisplace as the Mach number increases; Increasing the head dullness could effectively reduce the flux of the head. The average temperature on the head would be lower than the uniform conditions with calorically perfects gas. The above conclusion would take some reference value on the prime design of missles and prediction on the specific value of areodynamic heat.