三维随机填充球床通道内流场数值分析

Numerical Analysis of Flow Field in Three-Dimensional Randomly Packed Pebble-Bed Channel

对三维随机堆积球床通道内单相水流动进行数值模拟,分析了通道内沿流动方向不同位置截面径向速度分布,以及不同流动状态对截面速度分布的影响。其中球体随机堆积几何模型采用离散单元方法构建,并通过搭桥法对球体间及球体与管壁间的接触问题进行处理。研究结果表明:使用搭桥法后对孔隙率影响可忽略不计;球床通道截面速度与孔隙率具有相似的径向分布规律;在同一流动状态下,从管壁沿径向方向,不同截面的速度分布一致性逐渐减弱;随Rep的增加,同一截面速度分布趋于均匀。

The numerical simulations were performed on the water flow through three dimensional randomly packed pebble-bed channel,and the impacts of different flow conditions upon distribution of the radial velocity of cut section in packed channel were analyzed as well as different cut sections.The distinct element method was used to generate random packing structure,and the bridged method was used to deal with the contact issue of the particle to particle and particle to wall.The results show that using bridged method,the influence in porosity is negligible;the velocity in the cross section in packed channel has a similar radial distribution to porosity.The more distance away from channel wall,the worse consistency of the velocity distribution of different cross-sections.With the Reynolds number increase,the velocity distribution of the cross-section becomes uniform.