深空环境下液滴辐射相变过程分析模拟

SIMULATION ANALYSIS OF DROPLET PHASE-CHANGE PROCESS IN A DEEP-SPACE RADIATION ENVIRONMENT

太空中固体粒子比液体粒子对航天器危害性大,计算液滴相变时间和温度变化对评估粒子危害性有重要意义。本文建立了太空环境下液滴辐射相变模型,分析了三种相变凝固模型,估计了水滴蒸发量,考虑了太阳辐射对液滴温度变化的影响,分别计算了水和氧化铝液滴的温度变化。结果表明:液滴粒径越小液滴冷却速率越大,三种相变凝固模型的相变时间差别较小;水滴蒸发比例均大于10%,其蒸发量不可忽略;水滴受太阳周期性辐射时,其温度在50K至266K之间周期性振荡变化。

In space, solid particle does more harm than liquid particle to spacecraft. Thus, knowing phase-transition time and droplet temperature is significance for evaluating the danger of particle. In this paper, the radiation heat transfer model of droplet solidification is constructed in space surrounding. Then three types of droplet phase-change models are analyzed, and the quantity of water drop evaporation is estimated. Meantime, the effect of solar radiation on droplet temperature is taken into account. Finally, the water and aluminum oxide droplet temperatures are calculated, respectively. The results reveal that the cooling rate of droplet decreases with the increase of droplet diameter. However, there is few differences in phase-change time among these three models. The quantities of droplet evaporation exceed over 10% and hence can not be ignored. When irradiated cyclically by sun, the water droplet temperature oscillates periodically from 50 K to 266 K.