类Apollo返回舱外形肩部热流的数值影响因素分析

Factors in Calculating Heat Flux on the Shoulder of Apollo Like Reentry Capsule

预测类Apollo返回舱外形在高焓来流下的气动热特性研究网格Reynolds数、壁面温度、多种化学反应模型以及限制器对预测热流的影响.采用ESI-CFD-FASTRAN软件作为数值模拟平台使用基于温度梯度及分子扩散效应的热流模型空间离散采用Roe-FDS格式时间推进采用点隐式采用等温壁面条件.数值计算表明(1)热流在返回舱头部驻点处达到一个极值沿着壁面热流不断下降经过返回舱肩部热流有突越上升(2)满足网格Reynolds数小于10的网格获得的热流较为准确(3)使用Gupta模型计算得到的热流与Park85模型得到的类似但是获得的热流分布类似(4)采用湍流模型获得的头部肩部热流结果与层流结果相同(5)二阶min-mod限制器实现了高阶格式其计算得到的热流结果在肩部略高但是整体分布略低于不带限制器的格式.因此在计算中采用满足网格Reynolds数壁面网格采用带限制器的高阶格式计算获得的热流分布更加准确由于头部热流主要贡献并非来源于湍流因此对于肩部热流采用层流模型足够准确.

Simulation of the aerodynamic effect of Apollo reentry capsule under high enthalpy flow and the numerical factors influencing the predicted heat Ilow were studied.Employing ESI-CFD-FASTRAN software as the numerical simulation plat-form,the heat flux model based on temperature gradient and molecular diffusion effect was used.The spatial discretization used the Roe-FDS scheme,and the time marching used point implicit scheme.The numerical experiment shows that:(1)The heat flux reaches an extreme value at the stagnant of the mode,and the heat flow along the wall decreases continu-ously;(2)Grids satisfying the grid-Reynolds-number obtain accurate heat flux;(3)Gupta model calculated the heat flow is higher than that of the Park85 model,but the distribution is similar.(4)The turbulence model was used which obtain the same results as the laminar flow.(5)The second-order minmod limiter makes the heat flux on the shoulder relatively higher,but the overall heat flux distribution is lower than that of the non-limiter.Therefore,it is more accurate for predic-ting heat flux using mesh satisfying grid-Reynolds-number and using high-order-limiter;Gupta mode will obtain higher mag-nitude comparing to Park85 mode that will ensure the security in engineer application;Laminar mode results is the same as turbulence.