某发电厂循环水流道数值模拟

Numerical Simulation of Circulating Water Inlet Duct of Power Plant

针对某电厂发电机组循环泵水力振动,采用雷诺时均N-S方程结合标准湍流模型,对循环泵进水流道水流流态进行FLUENT三维数值模拟,研究了流道整体流场、水力旋涡、喇叭口区域流速和泵筒体区压力分布。研究结果表明,循环泵进水流道流场紊乱,流速大,旋涡严重,斜坡处回流区旋涡直径达3 m,泵体区域旋涡直径达5 m;泵吸入口水力条件恶劣,喇叭口区旋涡直径达3 m,流速不均,最高达0.9 m/s;泵筒体四周压力不均,南北两侧压差达500 Pa。

For solving hydraulic vibration of circulating pump of a power unit in a plant,the 3-D flow in circulating water inlet duct was simulated by FLUNET. The RANS equations and standard turbulence model were used in the numerical simulation. The flow fields and the hydraulic vortexes in circulating water duct were studied. The velocity fields in the region of the bell mouth and the pressure fields near the pump cylinder were also studied. The simulation results show that the flow fields are strongly disordered in circulating water inlet duct,where the velocity is high. Further-more,many vortexes happen in many key regions. The vortexes of diameter 3m happen in pressure forebay,and recirculation regions exist near the forebay slope. Many vortexes of diameter 5m also form in pump region. Hydraulic conditions of pump suction entrance are adverse. The velocity is non-uniform,max velocity is up to 0. 9m/s at the pump suction entrance,moreover,vortexes of diameter 3m happen in bell mouth region. The pressure is also non-uniform near the pump cylinder,the pressure difference between the north and south side is up to 500 Pa.