随机填充增殖剂球床内载气流动特性数值模拟

Numerical simulation of purge gas flow characteristics in randomly packed tritium breeder pebble bed

固态氚增殖包层是聚变堆及聚变-裂变混合堆产氚包层的重要候选结构之一,其球床通道内载气流动特性将影响氚提取效率。利用离散元方法(DEM)生成随机填充增殖剂球床,通过径向孔隙率分布验证其合理性,计算流体力学(CFD)模拟计算其通道内气体流场特征。模拟得到:球床内吹扫氦气流速随孔隙率波动并随入口流速增大而均匀增大,通道内氦气流向及流速变化显著,Blake-Kozeny方程可良好预测该随机填充球床通道压降。

Solid tritium breeder blanket is one of the most important blanket candidates for fusion reactor and fusion-fission hybrid reactor.The purge gas flow characteristics in the channels of pebble bed are important for the effective extraction of bred tritium from the solid breeder materials.A random packed structure of breeder pebbles,generated by Discrete Element Method(DEM),is verified by radial porosity distribution.The flow field parameters of the purge gas in channels are solved by Computational Fluid Dynamics(CFD)solver.The numerical analysis shows the velocity of the purge helium fluctuates with porosity distribution and uniformly increases with increasing inlet velocity,remarkable changes of flow direction and velocity occur in the channels.Blake-Kozeny equation is well applied to predicting the pressure drop in this random packed pebble bed.