高空气球热力学模型与上升过程仿真分析

Thermodynamic model and numerical simulation of high altitude balloon ascending process

基于对高空气球热力学环境的分析,建立了热力学与动力学耦合的高空气球动力学模型;并采用该模型对某高空气球的上升与驻留过程进行仿真分析.结果表明:高空气球上升过程中内部氦气存在"超冷"现象,其中平流层区域"超冷"明显,氦气平均温差为-19K;由于"超冷",其上升速度曲线呈双"V"形变化;强太阳辐射与弱对流环境使驻留过程中氦气呈现"超热"现象,平衡时氦气平均温度比环境温度高39 K,球内氦气超压648.8 Pa.数值仿真的速度、平均温度变化规律与相关飞行试验数据相吻合,说明该仿真模型是有效的.

Based on the analysis of the high-altitude balloon thermodynamic environment,a coupling dynamic model was established to describe its thermodynamics and kinetics.The model was used to simulate the ascending and floating processes of a high altitude balloon.The results show that the inner helium temperature will present ＂supercool＂ during its ascending process,and ＂supercool＂ is more pronounced during the stratosphere region,with the inner helium temperature 19K below the surrounding air temperature.Because of ＂supercool＂,its ascending velocity profile take on double ＂V＂ shape.The inner helium temperature presents ＂superheat＂ during the daytime floating process due to strong sun radiation and weak convection with air,and the inner helium average temperature is 39K higher than that of the surrounding air,with 648.8 Pa super-pressure.The ascending velocity profile and inner helium temperature profile of the numerical simulation good agreement with experimental flight data shows that the established model is accurate.