摘要
相变蓄热适用于周期性热流作用下航天器内部工作单元的温度控制,但是需解决微重力环境下相变材料融化速率低的问题.鉴于液态金属高导热系数和高单位体积潜热的特点,在微重力下将液态金属作为相变材料有望提高融化速率.通过对微重力下液态金属镓融化过程的相界面演化、流线和温度分布特征进行数值研究,分析了腔体尺寸和过热度对融化过程的影响.结果表明:微重力下镓的融化过程中,热传导起主导作用;镓的融化时间比冰和正十八烷分别减少了88.3%和96.4%,储热量分别为冰和正十八烷的1.2倍和2.2倍;融化时间随过热度增加而减小,随腔体半径增大而增大.此外推导出了液相分数随无量纲时间变化的关系.
Thermal energy storage is suitable for temperature control of working units in spacecraft under periodic heat flow,but it faces the problem of low melting rate of phase change materials under microgravity environment.In view of high thermal conductivity and high latent heat per unit volume of liquid metal,it is expected that the melting rate under microgravity will be increased by using liquid metal as phase change material.In the present study,the evolution of solid-liquid interface,streamline profile and temperature distribution during melting of gallium under microgravity are numerically investigated,and the influences of cavity size and superheat degree on melting process are analyzed.The results show that heat conduction plays a dominant role in the melting process of gallium under microgravity.The melting time of gallium is 88.3% and 96.4% shorter than that of ice and n-octadecane respectively,and the energy storage is 1.2 and 2.2 times of that of ice and n-octadecane respectively.The melting time decreases with the increase of superheat degree,and increases with the increase of cavity size.Meanwhile,the equation for describing the relationship between liquid fraction and dimensionless time is deduced.
作者
郭文华
彭浩
赵建福
GUO Wenhua;PENG Hao;ZHAO Jianfu(Engineering Research Center of Shipping Simulation,Ministry of Education,Shanghai Maritime University,Shanghai 201306;CAS Key Laboratory of Microgravity,Institute of Mechanics,Chinese Academy of Sciences,Beijing 100190;School of Engineering Science,University of Chinese Academy of Sciences,Beijing 100049)
出处
《空间科学学报》
CAS
CSCD
北大核心
2019年第6期778-786,共9页
Chinese Journal of Space Science
基金
上海市自然科学基金项目(19ZR1422300)
上海市青年东方学者人才计划项目(QD2016045)共同资助
关键词
微重力
液态金属
相变材料
融化
热毛细对流
Microgravity
Liquid metal
Phase change material
Melting
Thermocapillary convection
