运输机空投舱内压力动态变化数值模拟研究

运输机重装空投时，机舱横截面方向堵塞度较大，快速移动的空投物会造成舱内压力剧烈变化，甚至损害舱内乘员的身体健康，因此，有必要对运输机空投舱内压力的变化展开数值模拟研究。以运输机机舱内大型货箱在牵引伞拉力、重力、摩擦力以及气动力共同作用下 x 方向的变加速直线运动这一流固耦合问题为研究对象，基于运动嵌套重叠网格，对运输机重装空投前舱动态压力变化进行数值模拟，分析模型尺寸、来流速度、机舱堵塞度、投放位置等参数对舱内动态压力的影响规律，进而提出运输机重装空投风洞试验时与舱内压力相关的相似准则。结果表明：运输机执行重装空投任务时，空投物距离前舱位置越近，来流速度越大，堵塞度越大，空投时前舱动态压力变化越大，反之越小；风洞试验时，用空投前前舱压力值为参考量的舱内无量纲数是最准确、合适的舱内压力相似准则。

Numerical simulation of dynamic pressure change in transport aircraft cabin with airdrop

When heavy equipment are airdropped, the cabin cross-section is largely blocked, and rapid moving of heavy equipment will cause drastic changes in cabin pressure and even damage the health of cabin crew. Therefore, it is necessary to carry out numerical simulation of the pressure change in the airdrop cabin of the transport aircraft, and to lay a foundation for further research. In this paper, the fluid-solid coupling problem of variable acceleration linear motion in x direction under the combined action of traction pull of parachute, gravity, friction and aerodynamic force in the cabin of transport aircraft is taken as the research object, based on the motion overset grid. Numerical simulation of dynamic pressure variation in the forward compartment of a transport aircraft with heavy load airdrop is carried out. The results show that:(1) the closer the airdrop object from the frontal wall cabin, the higher the flow velocity and the bigger the degree of cabin cross-section blockage, the bigger the dynamic pressure change in cabin, and vice versa. (2) In the wind tunnel test, non-dimensional cabin pressure with reference of the front cabin pressure at the airdrop beginning is the most accurate and appropriate cabin pressure similarity criterion.