变截面烟道内导流板与布风板对再热器入口流场影响

Effect of Splitters and Air Distributor in Variable Cross-section Flueon Reheater Inlet Flow Field

为了分析导流板和布风板对变截面烟道内再热器入口速度分布均匀性的影响,基于N-S方程,首先对无导流板和布风板的原始烟道进行了三维流热耦合数值模拟研究;然后与仅安装导流板和同时安装导流板与布风板的烟道模型计算结果进行了对比。得到了三种不同结构条件下扩张段内流场,以及再热器入口截面速度场标准偏差系数的对比结果与变化规律。结果表明:(1)在无导流板和布风板的原始烟道中,烟气在扩张段内的速度分布极其紊乱,进而造成再热器入口速度分布极不均匀;(2)导流板的安装有利于提高再热器入口速度分布的均匀性,相对于无导流板和布风板的再热器入口截面的标准偏差系数C_v降低了15%;(3)布风板的安装不仅能够提高再热器入口速度分布的均匀性,而且能够改善布风板上游扩张段内部速度的分布情况,标准偏差系数C_v与无导流板和布风板的烟道流场结果相比降低了30.3%。

In order to investigate the effects of splitters and air distributor in variable cross-section flue on reheater inlet flow field,three-dimensional numerical simulations of fluid-heat coupling were conducted.The flue without splitters and air distributor has been studied numerically.The results had been compared with those of flue installed splitters only and flue installed splitters and air distributor.Change laws of standard deviation coefficient of the reheater inlet plane at three different conditions have been obtained.The velocity distribution in the divergent section had also been presented.The results show that in the flue without splitters and air distributor,the velocity distribution of the flue gas in the divergent section was quite turbulent,which was caused by the multiple turns and made the non-uniform velocity distribution of the reheater inlet plane.The installation of splitters could improve the uniformity of velocity distribution of the reheater inlet plane.Compared with the results of flue without splitters and air distributor,the standard deviation coefficient of the reheater inlet plane had decreased by 15%.The installation of air distributor could not only improve the uniformity of velocity distribution of the reheater inlet plane but also improve the velocity distribution in the divergent section.Compared with the results of flue without splitters and air distributor,the standard deviation coefficient of the reheater inlet plane had decreased by 30.3%.