低温流体微重力池沸腾气泡脱落特性研究  

Investigation on the Boiling Bubble Departure Behavior of Cryogenic Fluid in Microgravity

作　　者：马原[1] 孙培杰 李鹏 王磊[1] 厉彦忠[1] MA Yuan;SUN Peijie;LI Peng;WANG Lei;LI Yanzhong(School of Energy and Power Engineering,Xi’an Jiaotong University,Xi’an 710049,China;Shanghai Institute of Aerospace System Engineering,Shanghai 201108,China)

机构地区：[1]西安交通大学能源与动力工程学院,西安710049 [2]上海宇航系统工程研究所,上海201108

出　　处：《西安交通大学学报》2018年第9期89-94,共6页Journal of Xi'an Jiaotong University

基　　金：国家自然科学基金资助项目(51376142);航天低温推进剂技术国家重点实验室开放基金资助项目(SKLTSCP1810);陕西省博士后科研资助项目

摘　　要：研究微重力下的气泡动力学行为及其脱落特性是揭示微重力下流体沸腾换热机理的基础,而气泡处于空间复合弱力环境下,表现出不同于常规的特殊现象。以微重力下平板加热面上氢沸腾气泡为对象,展开了受力分析,考虑到Marangoni效应的影响,构建了受力平衡模型,进一步计算并分析了不同重力、压力、流体过冷度、壁面过热度下的气泡脱落直径。研究结果表明,当重力降低至某一临界值后,沸腾气泡存在3个不同尺度的脱落直径,且重力水平越低,气泡最大脱落尺寸越大,直径最大可达几十厘米。在常重力下,沸腾气泡仅存在0.01~0.1mm量级的脱落直径,压力对常重力与微重力下气泡脱落直径的影响差异显著,随着压力的升高,常重力气泡脱落直径不断减小,而微重力下最大气泡脱落直径有所增大;在微重力下,流体温度越低则过冷度越大,因此气泡最大脱落直径也越大,液氢过冷度每提高1K,最大气泡脱落直径增大约10%。当重力一定时,存在临界壁面过热度,且只有当壁面过热度超过该临界值时,沸腾气泡才会存在3个脱落直径。当压力越高、流体温度越低时,该临界过热度越小。The investigation on the bubble dynamics and departure characteristics in microgravity is the foundation to reveal the mechanism of boiling heat transfer under microgravity.Under microgravity,bubbles present different behaviors from that in normal gravity condition because of the comprehensive effects of several weak forces.Analyzing the force on a single hydrogen bubble on the plate heating surface and considering the Marangoni effect under microgravity,the bubble departure diameters are calculated for different gravities,pressures,fluid subcooling degree,and superheating degree of the wall.Results show that there might be three bubble departure diameters when the gravity is lower than a certain value,and the biggest departure diameter could increase to tens of centimeters as the gravity decreases.However,the bubble departure diameter in ground gravity is only at the scale of 0.01-0.1 mm,which shows that the effects of pressure on the bubble departure diameter are obviously different in normal and micro gravities.The bubble departure diameter declines in normal gravity,but the biggest departure diameter increases with the pressure in microgravity.Under microgravity,the lower the fluid temperature(means higher subcooling degree),the greater the biggest bubble departure diameter.The biggest departure diameter increases by about 10%with a 1 K increase of the subcooling degree.Under a certain microgravity,there is a critical wall superheating degree,and the existence of three different departure diameters depends on whether the wall superheating degree reaches the critical value.Higher pressure and lower liquid temperature result in lower critical superheating degree.

关 键 词：微重力 平板加热面 沸腾气泡 液氢贮箱 气泡脱落直径 

分 类 号：TK121[动力工程及工程热物理—工程热物理]