回转式空气预热器流场仿真分析

Simulation analysis of flow field of rotary air preheater

为分析某电厂1000 MW锅炉机组的双密封回转式空气预热器漏风问题,建立局部流体仿真模型。通过理论计算和仿真模拟相结合的方法分析了密封间隙对回转式空气预热器内部流场压力分布、密封压差及漏风率的影响,并针对“三密封”特殊时刻下的流场压力及漏风率变化做了研究。结果表明,密封间隙从2 mm到8 mm的变化过程中,密封片受到的最大压差小于7000 Pa;为使空预器漏风率小于5%,其漏风间隙需要控制在3 mm以内;“三密封”时刻下的漏风率达到了最小值,为3.98%。经过分析总结,为密封片的载荷计算及密封片的改进提供一定的参考。

To analyze the air leakage problem of the double-sealing rotary air preheater of a 1000MW boiler unit in a power plant,a local fluid simulation model is established.By combining the theoretical calculation and simulation,the influence of sealing clearance on the pressure distribution,sealing pressure difference and air leakage rate of the inner flow field of the rotary air preheater is analyzed,and the change of flow field pressure and air leakage rate on the special occasions of“three-layer sealing”is studied.Results show that when the sealing clearance increases from 2 mm to 8 mm,the maximum pressure difference of the sealing piece is less than 7000 Pa;in order to ensure that the air leakage rate of the air preheater is less than 5%,the air leakage clearance must be controlled within 3 mm;on the special occasions of“three-layer sealing”,the air leakage rate reached the minimum value of 3.98%.Based on above analysis and conclusions,this paper can serve as a reference for the load calculation and improvement of the sealing piece.