航天器密封舱微重力对流传热与传质地面试验模拟方法理论分析

Theoretical Analysis of Ground Testing Simulation of Heat and Mass Convection under Micro-gravity for Spacecraft

针对航天器密封舱内气体对流传热传质地面模拟试验问题,依据传热传质相似试验理论方法,进行了初步的理论分析,包括热缩比模型法和降压法,给出了它们相似试验的相似律及它们应用的约束条件,并从理论上定性分析了不同试验方法的优缺点。分析表明,在重力条件下,热缩比模型法在保持Reynolds数不变的前提下可明显抑制传热传质过程的温差和密度差对流动与传热传质的影响,而且抑制效果与缩比比例的三次方成正比;而降压法在保持Reynolds数不变的前提下同样可明显抑制自然对流的影响和密度差对流动与传热传质的影响,但对自然对流和传质过程的密度流的抑制效果有所不同。

The ground testing methodology on simulating micro-gravity heat and mass transfer of gas flow in pressurized cabins of spacecraft has been analyzed and discussed in the present paper, including thermal scale modeling and depressurizing modeling for reducing the gravity effect on heat and mass transfer. Their similarity criteria and application limitations are presented according to each different simulating testing technique. By the dimensionless parameter analysis and analogy, it is indicated that: (1) the thermal scale modeling can obviously reduce the effect of the temperature and density differences on the flow, heat and mass transfer under gravity condition with a constant Reynolds number, whose reduction is proportional to the third power of thermal scale.(2) the depressurizing modeling can also reduce their effect with the same Reynolds number, however, their reductions of the nature flow and the density difference flow are different.