直接空冷机组排汽管道流量分配特性数值模拟

Numerical Simulation of Flow Distribution Characteristics of Exhaust Steam Duct in Direct Air Cooling Unit

对某电厂1000MW直接空冷机组的排汽管道系统进行研究,建立处于高位布置的排汽管道上升管段的几何模型。利用流体力学软件Fluent对汽轮机处于不同工况下,管道内蒸汽流动情况进行模拟,得出机组不同流量下管道压损和流量分配特征并采用变管径的方法降低了压损,均衡各分配管流量。模拟结果表明:蒸汽流量大小对汽机排汽管道蒸汽分配情况基本无影响,通过增大支管管径的方法可以显著改善排汽管道流量分配不均现象。

By researching on the direct air cooling exhaust pipe system of IO00MW power unit, geometric model of the rising pipe section in the high position layout of steam exhaust pipe was set up. The stream flow in the pipeline was simulated using fluid dynamics software FLUENT when the steam turbine was working under different conditions and the result pressure loss of each pipe and flow distribution characteristics has been obtained. The method changing pipe diameter was used to reduce pressure loss and balance the distribution pipe flow. The results show that steam flow rate has no effect on the distribution of steam turbine exhaust steam pipe. By increasing the diameter of the tube, the flow distribution of steam pipe can be improved significantly.