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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。
With the angle coefficient as the starting point, the radiation heat transfer mechanism of the ball bed was studied. The analytical expression of the angular coefficient between two unit balls was derived under the spherical coordinate system. For the numerical calculation of angular coefficients, Monte Carlo method can achieve high computational accuracy and is suitable for large-scale parallel computation. In the ball bed due to the mutual blocking between the particle spheres, the angular decay between the two spheres is approximately zero at ball center distances of more than 2 times the ball diameter. Particles of voronoi cells are spatially divided into two parts. Particle spheres in the BCC, FCC and random stacking are all considered to be within the 2-layer Voronoi unit sphere. Particle spheres The number of 60 to 80. In the acceptable range, a large number of particle balls with weak radiation relation are ignored, which greatly simplifies the computational model of the ball bed radiation.