充气气囊减速方案的气动设计研究

Aerodynamic Design for an Inflatable Reentry and Descent Decelerator

减速是航天飞行器必须面对的问题。充气气囊减速方案利用柔性编织材料外加涂层方式构成气囊,利用气体发生器快速产生高压气体,集防热、减速和着陆减振功能于一体,重量轻、成本低、适用范围广、可靠性高。设计了满足减速需求的气囊外形,利用数值求解NS方程和工程计算方法进行了气动力的预测和比较分析,利用六自由度动力学模型与气动力的耦合计算,对减速效果进行了计算与分析,并对热环境、温度场、应力、热应力及变形进行了计算,还对分离不确定性进行了研究。地面引导性风洞试验和理论分析表明,充气气囊减速方案具有十分明确的减速效果和优点,可用于未来航天飞行器实现减速飞行目的的技术方案。

Aerodynamic deceleration is one of the key technologies for aerospace vehicles. Inflatable airbag deceleration concept uses high-strength flexible fabric, thermal protection coating and gas generator to form its speed breaking system, the functions of teat protection, deceleration and landing shock absorption are integrated. Because of light-weighted, low cost, high reliability and wide applicability, inflatable airbag technique is beneficial to vehicle aerodynamic deceleration and aerothermal protection distinctively. Based on a deceleration requirement hypothesis of a hitchhiking device, forward and backward airbag are designed to satisfy the drag demand, the aerodynamic characteristics are predicted and analyzed using NS equation solver and engineering method, consequently the backward one is confirmed because of its better stability. The deceleration effect is simulated coupling 6- D trajectory with aerodynamics prediction method, the heat flux, the temperature of the inner and outer coating surfaces, the stress, the heat stress and corresponding strain are investigated, and finally the flight behavior deduced by the uncertainty of separation release condition is discussed. The investigation of introductory wind tunnel tests and theoretical analyses indicates that the inflatable airbag concept is one of the feasible choices for vehicle deceleration, and worth to be investigated further in the future.