流化床内气固流体动力学的数值模拟

Numerical Simulation of Gas-particle Hydrodynamics in CFB

应用Fluent软件对一个比例模化后的130 t/h矩形截面循环流化床内的气固流体动力特性进行了数值模拟。模型预测结果和试验数据在一定程度上吻合良好。密相区颗粒运动受后墙渐扩截面的影响,对后墙形成较大的冲刷,因此应该对渐扩截面加强防磨保护。过渡区耐磨层的分析表明:炉内的不规则截面会形成局部漩涡和较多的颗粒冲刷,应该对耐磨层端面采用平滑过渡来减小磨损。出口结构布置会对整个系统内的颗粒流动模式产生重要影响。

The hydrodynamics of gas-solids flow in a scale model of 130t/h rectangular cross-section circulating fluidized bed were predicted by Fluent software. The modeling predictions compared reasonably well with experimental data. Particle movements in dense region were inclined to impact on back wall with the expanding cross-saction on back side. It＇s important to prevent the wear of expanding cross-section. Modeling and experimental results in transition region show that irregular structure in CFB would influence particle movements in this region greatly and cause local eddy which would cause acute wear on this cross-section. It＇s an effective step to adopt flat transition to reduce abrasion. Prediction and experimental results also show that outlet arrangement have important impact on whole system.