开“窗”结构对环帆伞开伞过程影响

Influence of‘windows’structure on inflation process of ringsail parachute

随着载荷重量的增加,单伞已无法满足大重量返回舱的安全着陆要求,群伞系统获得关注并成功应用。然而,伞间干扰等问题仍困扰着群伞的设计,新一代载人飞船已经考虑从透气性角度对此进行解决。同时,鉴于群伞开伞过程仿真难度较大,在不改变伞衣构型设计的前提下,采用流固耦合(FSI)方法针对单伞开展不同透气性的环帆伞开伞过程数值模拟,旨在研究开“窗”结构对环帆伞气动性能的影响。结果表明:开“窗”结构对环帆伞开伞过程中的外形变化有较小影响,开“窗”前后的伞衣投影面积与名义面积比变化最大不超过15%;对于不同的开“窗”位置和数量,平衡平均阻力系数、开伞动载系数及阻力系数波动三者的最佳选择为帆5位置和25%数量;采用开“窗”结构后的环帆伞最大摆角至少减小5°,且减小幅度随着开“窗”数量的增加而增大,但与开“窗”位置之间并无明显规律。

With increasing load weight,the inability of single parachutes to ensure safe landing of heavy reentry capsules diverts extensive attention to the cluster parachute system which has been successfully applied.However,the interference between the parachutes poses challenges to the cluster parachute design.The new generation of crewed spacecraft has attempted to solve this problem from the perspective of porosity.Due to the difficulty in simulating the inflation process of the cluster parachute,this paper adopts the Fluid-Structure Interaction(FSI)numerical method to conduct numerical simulation of the inflation process of single ringsail parachutes with different porosities without changing the configuration design of the canopy to investigate the influence of the‘windows’structure on aerodynamic performance.The result demonstrates that the‘windows’structure has minor influence on the shape change during the inflation process of the ringsail parachute,with the ratio change of the projected area to the nominal area before and after using the‘windows’structure no more than 15%.For different‘windows’positions and quantities,the best choice to balance the average drag coefficient,opening load,and fluctuation of the drag coefficient is sail position 5 and quantity 25%.The maximum swing angle is reduced by at least 5°after using the‘windows’structure,and the reduction will increase with the grow in the number of‘windows’;however,no clear patterns between the positions of the‘windows’is observed.