应急排气管道对主烟囱中速度及气体混合的影响

The influence of emergency exhaust pipe on the velocity and gas mixing in main chimney

应用计算流体力学(CFD)方法,模拟内部的应急排气管道存在与否对主烟道内气体组分混合的影响情况。以速度及示踪气体浓度的变异系数(COV)表征截面混合均匀性,对比研究了高风速(约13.1 m/s)、中风速(约8.2 m/s)、低风速(约0.56 m/s)三种典型工况。结果表明:主烟道内风速13.1 m/s,无内部管道可使速度及气体浓度分布更为均匀,各截面平均COV值分别降低2.8%和2.0%;风速8.2 m/s,无内部管道利于速度均匀分布(COV值降低1.5%),却降低气体组分的混合均匀性(COV值升高3.1%);风速0.56 m/s,速度和气体组分在无内部管道时呈现更好的混合均匀性,COV值分别降低4.8%和0.02%。对比仿真结果与实验数据,92.5%以上的仿真数据与实验值偏差低于15%。

The computational fluid dynamics(CFD)method is used to simulate the influence of the emergency exhaust pipe on the gas component mixing inside the main chimney.The coefficient of variation(COV)of velocity and tracer gas concentration are used to represent the mixing uniformity on each surface.Three typical working conditions were compared and studied,namely high wind speed(about 13.1 m/s),medium wind speed(about 8.2 m/s)and low wind speed(about 0.56 m/s).The results show that when the wind speed is 13.1 m/s and there is no internal pipe,the distribution of velocity and gas concentration is more uniform,and the COV values on each surface are reduced by 2.8%and 2.0%respectively;When the wind speed is 8.2 m/s and there is no internal pipe,it is conducive to the uniform distribution of velocity(COV value decreases by 1.5%),but reduces the mixing uniformity of gas components(COV value increases by 3.1%);When the wind speed is 0.56 m/s and there is no emergency exhaust pipe,the velocity and gas components show better mixing uniformity,and the COV values are reduced by 4.8%and 0.02%respectively.Comparing the simulation results with experimental data,more than 92.5%of the simulation data has a deviation of less than 15%from the experimental values.