喷腾分解炉内流场优化的数值仿真研究

Computational Investigation and Optimization of Flow Field in Sprayed Calciners

采用标准k-ε双方程模型和SIMPLE方法对喷腾分解炉内流动特性进行了数值模拟,通过增设分解炉的中部缩口、柱体的尺寸、入口气流的流速以及增加旋流风,在不同条件下得到了炉内的流场分布情况,并进行了比较和分析,为分解炉的结构和工况的优化设计提供了参考依据。研究表明:喷腾分解炉内流场主要为喷射流,不易产生较强烈的横向混合和必要的逆向物料返混。结构和工况参数的变化,延长了气流的运行轨迹,适当地增加气流的横向运动,将有利于延长物料的停留时间、物料的分散和煤粉燃尽率和CaCO3分解率的提高。同时,数值模拟结果将为优化分解炉设计和流动参数提供理论依据。

The flow field in the sprayed calciner was investigated using standard k-ε Model and SIMPLE method,flow field in the calciner can be attained by changing the middle-necking.the construction parameter of eylinder,the flow velocity of the bottom inlet and the velocity of swirl flow.The compared and analyzed results can supply references and information for optimization of flow-fields and construction design of the calciner.The simulation results demonstrate that the sprayed flow was mostly formed due to the sprayed effect;moreover,the transverse and converse mix of coal and raw materials was insufficient in the calciner.The delay of path line of flow and increase of transverse mix by changing the construction parameters and the operation conditions will be propitious to the delay of stop time of materials,coal combustion and the decomposition of CaCO3. Moreover,the simulation results can give the basis for optimizing the geometrical design and flow parameters.