燃煤机组冷却器入口烟道流场优化数值模拟研究

Numerical simulation on flow field optimization of cooler inlet flue duct in coal-fired units

燃煤机组的空预器出口后端有并联的三段烟道。在检修时发现,其烟道后端的烟冷器积灰严重情况不一。根据工程经验,该现象的可能原因为三段烟道流量分配不均,为改善系统阻力和流场均匀性,需对烟道结构及烟冷器布置形式进行优化。采用CFD数值模拟对某电厂燃煤机组冷却器入口烟道进行流场优化,重点分析了3种不同优化方案下烟道阻力、流量分配等参数的变化规律。结果表明:改变冷却器布置形式和烟道直径大小,并没有较好的改变流量分布均匀的问题,通过改变冷却器布置形式和架设导流板可以较好的使三段烟道流量分配保持一致,烟冷器本体可以较好的缓解积灰问题。

In coal-fired units,three flue ducts in parallel are configured at the rear end of the air preheater outlet.Serious ash accumulation at the rear end of smoke cooler was found in maintenance.The unevenness of flow distribution in three flue ducts is inferred as the possible cause.In order to improve the uniformity of flow field,it is necessary to optimize the flue structure and layout of smoke cooler.In this paper,CFD numerical simulation was used to optimize the flow field of inlet flue duct in a coal-fired power plant,and the varying pattern of flue flow drag and flow distribution under three different optimization schemes are analyzed.The results show that changing the layout of cooler and the diameter of flue duct have no obvious influence on improving the uniformity of flow distribution.By changing the layout of cooler and setting up a baffle,the flow distribution of three flue ducts can be improved,and ash accumulation problem can be alleviated.