泄压条件下绝热多孔材料的水蒸发速率研究

摘要

Water evaporation of airlock during pressure relief condition has great influence on rate and time of pressure relief when the pressure is lower than 2 kPa.There is no published study of pressure relief that focuses on water evaporation.This paper designed evaporation test to study the pressure relief process of the heat-insulating porous materials which was placed in the cabin under pressure relief con-dition.The experiment built the pressure relief environment based on the current ground test method, the cabin was divides into main and auxiliary cabin. The pressure relief condition was simulated by pumping the main cabin into vacuum pressure.At the same time,in order to compare with the pressure relief condition,we also carried out the evaporation experiment of the heat-insulating porous material under different constant pressure.Pressure interval is set to 10 kPa,low pressure condition is set at the midpoint 1 kPa between 2 kPa and 0 kPa.By measuring the mass of the porous materials placed in the cabin,the evaporation rate of porous materials under different conditions was obtained.The experimen-tal results show that the evaporation rate of water in the whole process of pressure relief is the fixed val-ue for 2.171 g/(min m2),which is independent of the pressure value and other factors.Under the con-dition of constant pressure,the inflection point will appear between 10 kPa and 1 kPa,and the evapora-tion rate on both sides of inflection point is fixed,respectively 0.870 and 2.141 g/(min m2).The ex-perimental results can support the study of influence of water evaporation on the pressure relief time of airlock.%航天器泄压过程中水分蒸发在低于2 kPa时对气闸舱泄压速率影响较大,并且影响泄压时间这一出舱活动指标,而检索后未见泄压条件下多孔材料水蒸发的研究.文中设计实验研究了航天器内壁铺设的绝热多孔材料在泄压条件下的水蒸发速率.实验参考目前气闸舱的地面试验方法搭建泄压环境,将试验舱分为主副舱,通过将主舱抽真空,副舱向主舱泄压来模拟超临界泄压状态.同时,为了与泄压工况进行对比,实验还进行了不同定压下的绝热多孔材料的蒸发实验.定压工况各压力间隔设置为10 kPa,低压状态设置为2 kPa到0 kPa的中点1 kPa.通过测量放置于舱内的吸水多孔材料的质量,实验获得了不同工况下多孔材料的蒸发规律.实验结果表明,在泄压工况下,泄压全过程中水的蒸发速率均为定值,为2.171 g/(min·m2),与压力值等因素无关.在定压工况下,在10 kPa向1 kPa转变时会出现拐点,拐点两边的蒸发速率均为定值,分别为0.870和2.141 g/(min·m2).实验结果可为研究水蒸发对气闸舱泄压时间的影响提供支持.