导流装置对汽轮机排汽通道流动特性的影响

摘要：采用RNG 模型对某600MW机组低压排汽通道内气动特性进行了三维数值研究，研究了排汽通道内流场分布并提出三种不同的导流方案对排汽通道内的流场进行优化改造。研究结果表明：排汽缸上部通道中气流呈漩涡流动，通道内排汽压力损失增加；在喉部出口截面每1/4区域内都有一个漩涡，相邻的两个漩涡之间流场分布不同；加装导流装置能够有效破坏流场中的漩涡结构，改善通道内的流场分布；在机组变负荷运行时，不同的优化方案同样适用；低负荷运行时，三种不同方案压力损失数值变化不大，方案三中喉部加装四块导流板时喉部出口流场均匀性最好。

Influence of guiding device on flow characteristics in exhaust passage of stream turbine

The aerodynamic characteristics of the low pressure exhaust passage in 600MW unit were simulated by using the RNG model. The flow field in exhaust passage was studied and three different flow guiding devices were put forward to optimize the flow field in exhaust passage. The results indicate that the exhaust pressure loss increases due to the vortex in upper passage of exhaust hood. There is a vortex in each quarter area of the throat outlet, and the flow field distribution is different in the two adjacent vortexes. The flow guiding device can destroy the structure of vortexes effectively and improve the distribution of flow field in the passage. The different optimization schemes are feasible in variable load operation of power units. The pressure loss in three different schemes changes little under the low load. The flow field uniformity in the outlet of throat is the best for the scheme three with four flow guiding devices.