变截面倾斜烟道导流板对AIG入口流场的影响

摘要

To optimize the velocity distribution of AIG inlet, the design for splitters of variable cross-section flue at the AIG upstream was researched in a coal fire plant selective catalytic reaction (SCR) system. The velocity distribution of AIG upstream with variable cross-section flue was simulated by Fluent software, the effect of uniform splitters installation angle and different installation angle in variable cross-section flue on flow field of AIG inlet was researched and the change of flow field distribution was analyzed. The results show that in the condition of uniform installation angle, the guiding effect of splitters makes the velocity distribution at the two walls perform inverse trends, these two conteracting trends nullify the effect of the splitters and make the Cv value lowest, 15. 4% at installation angle of 64°. However, the velocity distribution near two walls at the Z direction is still not uniform. Then a new optimization design method using different installation angle near two walls is put forward, the results show that the optimization design can improve the uniformity of velocity distribution near two walls and makes the Cv value decrease from 15. 4% to 12. 4%.%结合某实际电厂选择性催化还原(SCR)系统,对该系统喷氨格栅(AIG)上游变截面烟道处导流板的布置进行研究,以优化AIG入口的速度流场分布.基于fluent软件,对带有变截面烟道的AIG上游的速度流场进行数值模拟,研究变截面处导流板等角度布置方案和变角度布置方案对AIG入口流场的影响,并分析流场分布变化的原因.结果表明,在等角度布置的条件下,导流板的引流作用使Z向两壁面处的速度分布随角度变化呈现相反的趋势,并在布置角度为64°时标准偏差系数Cv值最低达到15.4％,但靠近两壁面处的速度分布仍不均匀.针对这种情况对导流板进行了变角度优化布置,结果发现,优化方案可以提高两壁面处速度分布以及AIG上游整体速度分布的均匀性Gv值从15.4％降至12.4％.