1000MW机组直接空冷系统排汽管道流动特性

Flow characteristics of exhaust pipes in a 1 000MW direct air-cooled unit

以某1 000 MW机组直接空冷系统为例,采用计算流体动力学(CFD)软件对分散式布置与高位和Y型布置排汽管道的流动特性进行模拟计算和分析比较。结果表明:排汽管道分散式布置2较其他布置方式的流量分配均匀性高,可减小各个散热单元的流量差异,减少了大直径管道的应用,较大幅度地减少材料消耗;相同流动条件下,分散式布置2的流动阻力高于高位和Y型布置约20Pa。因此,在实际工程设计中,可选择分散式布置2作为排汽管道的布置方式。

Focusing on the steam flow distribution and flow resistance problem of the exhaust pipe in a 1000 MW direct air-cooled system,the flow characteristics for the different piping layouts,including the scatter type,the conventional Y-type and high position-type were simulated and compared by using the computational fluid dynamics（CFD）method.The results show that,the scatter type piping layout scheme II improves the uniformity of flow distribution,minimizes the flow distribution difference between each cooling unit,reduces the consumption of large diameter pipes,and significantly decreases the material cost.However,the disadvantage of the scatter type piping structure（scheme II）is to create a high flow resistance,the pressure drop increases about 20 Pa compared with that of the Y-type and high position-type piping layouts under the same flow conditions.Therefore,during the actual engineering design,the scatter type piping layout scheme II can be selected as the arrangement scheme for exhaust pipes.