盘缝带伞超声速开伞过程研究

Study on the Deployment of Disk-gap-band Parachute in Supersonic Flow

随着深空探测着陆的发展,对降落伞超声速开伞的研究迫在眉睫。文章采用守恒元/解元算法对美国某空投试验所用盘缝带伞进行超声速开伞过程的仿真模拟,将数值仿真得到的伞衣充满外形和最大开伞动载与此盘缝带伞的高空投放试验进行对比,获得较为一致的结果,验证了数学模型的可靠性。在此基础上,继续对此盘缝带伞超声速开伞过程进行详细研究,分析了开伞过程伞衣充气外形变化、开伞动载变化、伞衣应力分布以及伞衣不同位置的应力随时间的变化情况。结果表明,开伞过程中伞衣会存在一定的"呼吸"现象,同时在伞衣口处会形成一道弓形激波。开伞动载在经历了较大的波动后逐渐稳定,伞衣盘上的应力比伞衣带上的应力值大。因此,在盘缝带伞的设计中应着重考虑伞衣盘部分的强度要求。

With the development of deep space exploration and landing, it is urgent to study the deployment of parachutes in supersonic flow. In this paper, the Conservation Element and Solution Element Method（CE/SE method） incorporated in the LS-DYNA code is used to simulate a full flexible disk-gap-band parachute which is used in an airdrop test flying in supersonic flow. The full inflation shape of canopy and the maximum of dynamic load of the simulation are in agreement with those obtained in high altitude flight tests of the same parachute, which verifies the reliability of the mathematical model. The process of the inflation is studied in detail, including inflation shape and opening load of the parachute. In addition, the variation of stress and stress distribution of the parachute with time are also presented. The results show that the canopy experiences some ＂breathing＂phenomenon in the process of deployment. At the same time, the mouth of the canopy forms a bow shock. Opening load of the parachute is stable gradually after a large fluctuation; the stress on the disk is higher than that of the band. Therefore, in the design of disk-gap-band parachute, the strength requirements of its disk part should be considered more.