整流板对T型分流三通管局部阻力特性影响的数值研究

Numerical study on effect of rectifier plate on local resistance of branching tees

三通管的阻力特性对管网系统的流量分配及经济输送有着显著影响。以某电厂热一次风管道中的T型分流三通管为研究对象,采用Fluent软件对安装整流板后的三通管道进行数值模拟,分析不同形式整流板对三通管内流体阻力特性的影响,并通过能量耗散分布分析了整流板的减阻机理。模拟结果表明:安装整流板后,侧支管局部阻力系数ζ01明显减小,其中基于流场特征确定的方案3减阻效果最好;整流板高度对ζ01影响较大,当流量比q较小时,ζ01随整流板高径比h增加而减小;q较大时,随h增加,ζ01先减小后增加,其中h=0.38时减阻率最大,为40.6%;整流板长度对ζ01影响较小,q较小时,ζ01随整流板长径比l的增加小幅度降低;q=0.6时,随l增加,局部阻力系数先减小然后趋于不变,其中l=3.13时减阻率最大,为40.2%;q较大时,随l增加,ζ01略微增大。

The flow resistance characteristics of tee pipes have a significant impact on the flow distribution and economic transportation in pipe network systems. Taking a branching tee in the hot primary-air pipe of a power plant as an object, the Fluent software was applied to numerically simulate the hydrodynamics of the pipe tee after installing rectifier plates. The influence of different rectifier plates on the local resistance was investigated, and the drag reduction mechanism was explained with energy dissipation distribution. The results show that, after installing rectifier plates, the local resistance of the side branch pipe is significantly reduced, and the scheme Ⅲ based on the characteristics of flow field is the best for drag reduction. The height of the rectifier plate has a notable impact on ζ01. For a low flow ratio q, ζ01 decreases with the increase of the height-diameter ratio h of a rectifier plate. For a high q, as h increases, ζ01 decreases at first and then increases, where the maximum drag reduction rate of 40.6% is observed at h=0.38. The length of a rectifier plate has negligible influence on ζ01. When q is small, ζ01 decreases slightly with the increasing length-diameter ratio l. When q=0.6, as l increases, the local drag coefficient decreases at first and then tends to remain unchanged, where the maximum drag reduction rate(40.2%) is found at l=3.13. When q is large, ζ01 raises slightly with the increasing l.