临近空间飞艇内部自然对流的流场特征仿真

Simulation on flow field characteristics of natural convection inside near space airship

针对临近空间飞艇,对其内部氦气的自然对流特征进行了数值模拟。采用计算流体力学方法,并利用自编的用户自定义函数将外部的温度边界条件导入壁面网格。在不同的稳态条件下,通过对内部氦气压力、温度、速度的分布等流场特征参数的研究,分析了临近空间飞艇内部气体自然对流的运动特性及其影响规律,并对自然对流非稳态变化过程进行了初步的探索。仿真结果表明,在临近空间环境下,飞艇内部氦气的自然对流,对于内部氦气自身的热交换具有一定程度的促进作用,而对蒙皮受力和结构安全性影响很小。

Aiming at the near space airship, the natural convection characteristics of the helium inside an airship were simulated numerically. On the basis of the computational fluid dynamics method and user-defined function, external temperature boundary condition was imported into the wall grids. Under conditions of different steady states, the motion characteristics and influence regulations of gas natural convection inside the airship were analyzed by researching the characteristic parameters of flow field, such as distribution of pressure, temperature, speed. Besides, the unstable change process of natural convection was also studied preliminarily. The simulation results show that natural convection of helium inside a near space airship has some active influence on heat exchange of inside helium, but the influence is very weak on stressed skin and structural safety.