Calculation of transient temperature rise of dome under laminar heat transfer condition and improvement of dome structure

Aiming at the problem of thermal barrier effect, transient temperature rise of sphere dome was calculated by fluid-solid coupling method, and then the structure of dome was improved. Based on wind tunnel and rocket sled tests, as well as analysis of the potential of vorticity interaction in entropy layer, the critical Reynolds number based on the free stream parameters and the diameter of dome which could be used to judge the flowing state over sphere dome was proposed as 2.7106. Compared with the experimental data, the laminar heat transfer formula of Van Driest based on isentropic relations was found to be applicable for the calculation of heat transfer for the most area of hemisphere dome. Based on Van Driest's formula and finite element method, the heat transfer of dome was calculated to obtain the transient temperature field of sphere dome. The results show that temperature rise of dome is relatively fast and the trajectory should be well designed to avoid thermal barrier effect. For the requirement of high speed long-endurance system, a composite optical dome structure was designed based on porous ceramic, which could extend the flight time significantly and compared with side-window system, the aero-optic effects caused by the new composite dome was small. The new composite optical dome is suitable for long wave infrared optical systems. Thermal shock stress in composite optical dome is smaller, and because of conformal shape, the aerodynamic drag of composite optical dome is smaller also. Then the composite optical dome can be flexibly applied under the flight conditions of high mach number and low altitude.