内嵌定向高导热层疏导式结构热防护机理分析

Analysis of thermal protection mechanism of leading structure embedded high directional thermal conductivity layer

针对飞行器高超声速飞行时严重的气动加热环境,提出内嵌定向高导热层的疏导式热防护系统.运用数值方法分析了特定条件下内嵌定向高导热层的疏导式系统的防热效果,外壁面最高温度下降了9.1%,内壁面最高温度下降了31.5%,高温区和低温区都被封闭在外层区域,内层温度更加均匀,实现了热流由高温区向低温区的转移,削弱了高温区的热载荷,强化了整体结构的热防护能力.研究表明,随着气动热流密度比与辐射散热面积比的增大,疏导结构的冷却效果增强.本文还对疏导防热系统的结构参数和材料参数对冷却效果的影响进行了分析,为结构的设计和材料的选取提供一定的依据.

The structure of embedded high thermal conductivity layer leading thermal protection is considered as thermal protection system to prevent hypersonic vehicle from the serious aerodynamic heating. By numerical method, we analyze the cooling effect of the leading thermal protection system under given conditions. The maximum outer surface temperature and the inner surface temperature are reduced by 9.10% and by 31.5% respectively. Both high temperature region and low temperature region are blocked in the external layer and the inner temperature distributions are more uniform. The transfer of heat from high temperature region to low one is achieved, the thermal load of the high temperature area is weakened, and the ability of leading thermal protection system is strengthened. The research shows that the cooling effect of leading system increasing with the increasing of aerodynamic flux ratio and the area ratio of radiative surfaces. The influences of structure parameters and materials properties on thermal protection are discussed, which provides some references for the design of the structure and the selection of materials.