摘要
以角系数为切入点研究球床辐射换热机理,在球坐标系下推导出2个单位球之间角系数的解析表达式。对于角系数的数值计算,蒙特卡洛法可以达到很高的计算精度,适合用于大规模并行计算。在球床中由于颗粒球之间的相互阻挡,在球心距超过2倍球径时2个球之间的角系数近似衰减为零。利用voronoi单元体对球床进行空间局部划分,在体心立方(BCC)、面心立方(FCC)和随机堆积中近似认为所有存在辐射关系的颗粒球均在2层Voronoi单元球内,颗粒球数量为60~80个。在可接受的范围内忽略了大量辐射关系极弱的颗粒球,大幅度简化了球床辐射计算模型。
In this paper, the mechanism of radiation heat exchange for high temperature pebble beds is studied by view factor, and the analytical solution for view factor between two unit spheres is derived. Compared with various numerical methods for view factors, Monte Carlo Method (MCM) is selected with high accuracy and good parallel performance. As blocked by other particles, the view factor between particles approximately is reduced to zero at distance of double sphere diameter. With spatial local partition by Voronoi tessellation, for body center cube (BCC), face center cube (FCC) and random packing all particles interacted by thermal radiation are included among double Voronoi spheres, about 60-80 spheres. Within acceptable range many particles with extremely low view factor are neglected, numerical radiation model is greatly simplified.
出处
《核动力工程》
EI
CAS
CSCD
北大核心
2016年第2期32-37,共6页
Nuclear Power Engineering
关键词
高温球床
辐射换热
角系数
解析解
Voronoi单元体
High temperature pebble beds, Radiation heat exchange, View factor, Analytical solution, Voronoi Tessellation