平流层零压气球飞行控制仿真研究

Numerical simulation study on flight performance of stratospheric zero-pressure balloon

文章在详细分析零压气球几何外形、内外热环境和受力等情况的基础上,建立了零压气球几何、热力学和运动学模型。基于该模型,对零压气球上升-驻空-下降全过程进行了仿真模拟,得到零压气球飞行高度、蒙皮及内部气体(氦气)平均温度、氦气质量、气球体积以及气球飞行速度随时间的变化规律,并讨论了气球充氦量以及放飞时间对气球飞行性能的影响。结果表明:气球在上升过程中,氦气存在严重的"超冷"现象,而在驻空和下降过程中,出现严重的"超热"现象。由于"超冷",气球上升速度曲线呈"W"型变化;中午过后,随着太阳辐射的减弱,气球开始下降,直至降到地面。此外,充氦量及放飞时间直接影响到上升过程中氦气温度和飞行速度,对气球驻空高度影响很小。

The geometrical, thermodynamic and dynamic models of the zero-pressure balloon were established on the basis of detailed analysis of geometrical shape, internal and external thermal environment, and force of the balloon. Based on the mathematical models, the flight performance during the ascending-floating-descending processes of a zero-pressure balloon was simulated, the variations of the flight velocity and height of the balloon, the membrane and inner gas average temperatures, the mass of helium gas and the volume of the balloon were investigated, and the effects of the helium gas mass filled into the balloon and the launch time on the flight performance were explored. The results indicated that the inner gas temperature presented “supercool” during the ascending process and presented serious “superheat” during the floating and descending processes. Due to “supercool”, the ascending velocity profile assumed “W” shape. After noontime, the balloon began to descend with the reduction of solar radiation, until it dropped to the ground. Besides, the mass of filled gas and the launch time directly affected the inner gas temperature and the flight velocity, and had no effect on the floating height of the balloon.