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 ζ_(01). For a low flow ratio q

ζ_(01) decreases with the increase of the height-diameter ratio h of a rectifier plate. For a high q

as h increases

ζ_(01) 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 ζ_(01). When q is small

ζ_(01) 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

ζ_(01) raises slightly with the increasing l.