电站循环水泵进水流道水力特性及整流优化研究

循环水泵进水条件的优劣对循环水泵效率及是否出现汽蚀和振动有显著影响。针对某电站300 MW机组循环水泵振动问题,采用RNG湍流模型对其进水流道水力特性开展三维数值模拟研究,分析了进水流道整体水流流态、泵吸水喇叭口附近区域流场、泵体周围流速分布,并对其进行了整流优化改造方案研究。结果表明,循环水流道斜坡坡度较大,导致水流扩散不均匀,表面流速较大,在斜坡底面和进水池存在较大漩涡;泵吸水喇叭口截面水流严重不对称,出现较明显偏流,泵进水条件恶劣;采取有效整流消涡措施可以改善循环水流道水流流态,均匀流速,改善泵进水条件。

Hydraulic Characteristics and Rectification Optimization of Circulating Water Pump Inlet Duct of Power Plant

The advantages and disadvantages of circulating water pump inlet condition have a significant impact on circulating water pump efficiency and whether appear cavitation and vibration. In view of the vibration of the circulating water pump in a 300 MW power plant, the three-dimensional numerical simulation of the flow pattern of the circulating water inlet duct was carried out by using the RNG k-ε turbulence model. The whole flow field, the flow field in the region of the bell mouth and the velocity distribution around the pump body were studies. And the corresponding rectification optimization measures were presented. The results show that the slope gradient of the circulating water inlet duct is sharply, which leads to the uneven flow diffusion and large water surface flow velocity. There is a large vortex in the bottom of the slope and the intake sump. The bell mouth section exists water serious asymmetry phenomenon and appear obvious bias, so the pump inlet conditions are poor. Effective rectification and eliminating vortex measures can be taken to improve the flow pattern and even flow rate, and improve the inlet condition of the pump.