超声速透气降落伞系统的气动干扰数值模拟研究

Numerical Simulation of Aerodynamic Interaction of Supersonic Porosity Parachutes

盘–缝–带伞是目前主流的火星用超声速降落伞,然而由于其阻力性能的限制,新一代的火星探测任务已经开始考虑采用环帆伞来获得足够的阻力性能。同时,在超声速条件下,由于稳定性的需要,透气性对降落伞系统减速性能的影响研究日益受到重视。文章基于计算流体力学方法对不同孔隙率的降落伞系统模型进行数值模拟,旨在分析开缝位置及孔隙率对环帆伞气动性能的影响机理。结果表明:在马赫数为2的大拖拽距离比条件下,无缝环帆伞系统流场与盘–缝–带伞有较大区别,主要表现在伞前激波的形成过程及前体尾流和伞前激波的作用阶段上。此外,开缝产生的孔隙率对环帆伞的减速性能有较大影响。开缝伞形的阻力性能劣于无缝伞形,但稳定性能显著高于无缝伞形。而前缝伞形的稳定性能及阻力性能均优于后缝伞形。该结果对超声速降落伞的伞型结构透气性参数设计有一定的参考价值。

Disk-Gap-Band parachute is mainly applied in the rescent Mars explorations.However,due to limitation of its drag performance,in the future Mars mission,ringsail parachute has already been considered to provide a high enough drag coefficient.Furthermore,in order to improve the parachute stability in supersonic speeds,the research on the influence of porosity on the aerodynamic performance of parachute system has been paid more and more attention.Based on the computational fluid dynamics(CFD)method,the parachute system models with different porosities are simulated to analyze the effect of the porosity and its position on the aerodynamic performance of the ringsail parachute system with a large trailing distance at Mach number 2.The result demonstrated that although the flow field mode seems similar between the ringsail and the disk-gap-band parachute system,there are contrasts in the formation process of the canopy shock,the interaction between the capsule wake and the canopy shock.In addition,the geometric porosity generated by the gap has a great influence on the performance of the ringsail parachute,the gap causes the drag become smaller and the stability become better.Moreover,the drag and stability performance of ringsail parachute with the front gap are better than that of the ringsail parachute with rear gap.The results can be applied as a reference for the design of geometric porosity for the future supersonic parachute system.