火星着陆发动机气凝胶材料热防护装置设计

Design of aerogel-based thermal protector for Mars landing engine

大推力着陆发动机高温热防护技术对火星着陆任务安全至关重要。基于多级热辐射反射结构的常规发动机高温隔热屏在火星大气环境中使用时,因内部气体换热导致隔热性能显著衰减。为解决这一问题研发了一种基于气凝胶隔热材料的新型发动机热防护装置。根据火星探测工程任务服役环境防隔热需求,建立了考虑低压气氛与高温热流边界影响的瞬态传热模型,开展了新型隔热系统的外形锥度、隔热层厚度等关键结构参数的优化设计,通过三维瞬态仿真分析及与发动机联合试车地面试验验证了设计有效性。气凝胶热防护装置成功应用于天问一号火星着陆巡视器,实现了对着陆发动机1500℃超高温的有效屏蔽。对在轨遥测数据进行反演分析,提出了基于气凝胶材料的高温隔热设计的优化改进方向。

The thermal protection technology for the large thrust landing engine is crucial for the safety of Martian landing mission.When the conventional high-temperature thermal shield based on the multi-stage heat radiation reflection structure is used in the Martian atmospheric environment,its heat insulation performance is significantly attenuated due to internal convection heat transfer.To solve this problem,a new type of engine thermal protector is developed based on the aerogel material.According to the operation environment for Mars exploration mission,transient simulation models with both low-pressure atmosphere and high-temperature heat flux boundaries are established,and the key design parameters such as shape taper and material thickness are optimized.The effectiveness of the design is verified by three-dimensional transient simulation analysis and the ground test with landing engine.The aerogel-based thermal protector has been successfully applied to the Tianwen-1 Mars lander,which has effectively shielded the landing engine from a high temperature of 1500℃.Based on the analysis of on orbit telemetry data,directions for improving the high temperature insulation technology based on the aerogel material are proposed.