防热大底外形对火星探测器气动特性的影响分析

Investigation on Influence of Heatshield Shape Changes on Aerodynamic Design for a Mars Entry Capsule

采用基于等效比热比的数值模拟方法,研究球锥和球头两种类型的火星进入探测器防热大底形状。对于每种外形分析关键几何参数对探测器基本气动性能的影响,并比较两类防热大底形状气动特性的差异。与球头形状的防热大底布局相比,球锥形状的防热大底布局一般阻力更大,对流加热量也更大,气动稳定性裕度更小。研究结果表明,从气动性能的角度来讲,70°半锥角的球锥防热大底布局对于火星进入探测器的设计而言并非最优的选择,适当设计的球头防热大底布局能够具有更好的性能。

Two types of heatshield shapes, i. e. , sphere-cone and sphere, are investigated by numerical simulation based on equivalent specific heat ratio. For each type of heatshield shape, parametric studies of the key geometric parameter are conducted to investigate the influence of the key geometric parameter on basic aerodynamics of the capsules. Comparison of the aerodynamic characteristics between the two types of heatshield shapes is made. In general, the spherecone heatshield configuration has greater drag, greater convective heating and less aerodynamic stability margin compared to the spherical heatshield configuration. Further investigation suggests that the 70° half-cone-angle sphere-cone heatshield shape is not the best choice for Mars entry capsule design from the perspective of aerodynamic performance, and the properly designed spherical heatshield configuration has a better performance.