以某火电厂锅炉尾部烟道为研究对象，运用CFD仿真计算技术，对锅炉尾部烟道进行建模计算，分析了改进前后烟道流场及阻力分布。结果表明:该电厂原有烟道A、B侧增压风机出口至二级烟冷器前烟气流动阻力为944 Pa，现场试验测试该段烟道阻力为890 Pa，相对误差为6%，模拟计算压力数据与现场试验测量压力数据结果基本吻合，且该段烟道内流场分布不均匀，烟气流动过程中存在很多涡流区域。提出四种改进方案：方案一取消上升段烟道，将烟道置于地面；方案二在方案一的基础上，在两侧烟气汇合处及弯头处增加导流板；方案三由烟气中间汇合改为单边汇合；方案四采用圆形烟道。四种改进方案可分别将该段烟道阻力降至500、400、317和105 Pa。方案三及方案四对于烟气阻力降低的效果较明显，但方案四烟气流速均匀性分布效果较差。综合阻力及速度分布情况来看，改进方案三更加合适。

With the tail flue of a thermal power plant as the research object,the CFD simulation technology was used to model and calculate the tail flue of the boiler,and the flow field and resistance distribution of the flue before and after the improvement were analyzed.The results show that the flow resistance of the flue gas before the outlet of the original flue A and B of the power plant to the secondary smoke cooler is 944 Pa.The field resistance is tested at 890 Pa,with 6% relative error.The simulation pressure results are essentially consistent with the field test data.The flow field distribution in the flue section is not uniform,and there are many eddy areas in the flue gas flow.In this paper,four improvement schemes are proposed.In the first scheme,the flue is placed on the ground and without upright section.For the second scheme,the baffles are added at the confluence of the flue gas and the elbow based on the first scheme.In the third scheme,the middle confluence of the flue gas is modified to unilateral confluence.The fourth scheme uses a circular flue.All four schemes reduces the flue resistance to 500,400,317 and 105 Pa,respectively.Schemes 3 and 4 are more effective in the reduction of smoke resistance,but Scheme 4 has a poorer effect on the uniformity of smoke flow rate.In terms of comprehensive resistance and speed distribution,Scheme 3 is a better candidate.

TM621

国家自然科学基金（51876109）；国家重点研发计划（2017YFD0400902-1）