CFB用旋风分离器内气相流场的数值研究

采用RSM非稳态湍流模型对循环流化床锅炉用旋风分离器内气相流场进行了数值模拟。计算值与实验值比较吻合。数值计算的结果表明:排气管下口存在明显的短路流,排尘口附近存在明显的返混现象;排气管直径增加,分离空间切向速度值降低,上行流轴向速度减小。用CFD方法计算的旋风分离器内流场可为高效CFB锅炉用旋风分离器的设计提供参考依据。

Numerical Simulation of the Gas Flow in the Cyclone Separator used in the CFB Boiler

The gas flow field in cyclone separators for the usage of circulation fluidized boiler (CFB) was simulated by the RSM unsteady turbulence model. Results obtained by this model are in good agreement with the experimental ones. The numerical simulated results showed that, there was an evident shortcut flow at the bottom of the vent and a bypass-and-mixing phenomenon exited nearby the discharge dust. An increase of the vortex finder diameter gives rise to a decrease of the tangential velocity of separation space and the upward axial velocity; the flow field calculated with CFD method provides valuable guidance for designing efficient cyclone separators for CFB usage.