流构耦合作用下柱状薄膜充气过程的流场

采用Euler-Lagrangian方法,重点研究了柱状薄膜充气过程的流场特性.研究表明:在入口气流速度为50~90m/s,入口气流压力为1.0~1.4MPa条件下,柱状薄膜在充气初始阶段,两端会出现上下摆动的鼓包现象.通过分析柱状薄膜内部流场中的气流组织、涡量输运以及旋涡与激波相互作用,发现气流在充气口附近形成弧形激波,使流动发生偏转.偏转气流在充气口两侧形成旋涡,和激波相互作用形成局部超声速区.另一方面,对柱状薄膜应力分布的研究发现,充入气流造成柱状薄膜顶部与两端的局部应力集中,是影响稳定性与安全性的重要因素.不同入口气流压力与速度条件下柱状薄膜应力分布与摆动情况表明,入口气流压力的变化对安全性的影响相对重要,而入口气流速度对稳定性的影响更加显著.

Flow field of cylindrical membrane inflation under the fluid-structure interaction

Numerical research on the flow field characteristics of the cylindrical membrane inflation was performed by the Euler-Lagrangian method. The results show that bumps are formed at two ends of the cylindrical membrane, swinging vertically during the inflation within inlet velocity range (50-90m/s) and inlet pressure range (1.0-1.4MPa). With the analysis on the flow structure, vorticity transportation and the mechanism of vortex/shock interaction in the flow field inside the cylindrical membrane, it is found that there is a cured shock adjacent to the inlet tube, making flow deflection. Vortexes formed by the deflected flow interact with shock, resulting in local supersonic zones. Based on the discussion about cylindrical membrane stress distribution, the local stress concentrations at the top and two ends of the cylindrical membrane are considered as important factors influencing the safety and stability. Comparing the results of different inlet pressures and velocities, it is found that the influence on safety caused by the inlet velocity is less than the inlet pressure, and the influence on stability caused by the inlet velocity is greater than the inlet pressure.