Hydraulic experimental study of a hydropower station's inlet shape optimization

By using the hydraulic model test to one thirtieth scale,the inlet flow pattern,vortex characteristics,inlet section head loss,time-average pressure characteristics,and gate velocity are studied.The result of the test shows that within the normal water level of the hydropower station,hazardous vortex does not appear in inlet to affect the normal operation,and the design of inlet and trash rack structure is rational.The hydraulic loss coefficient between trash rack structure and the end of the transition section of inlet is 0.122.Under the condition of an unit diversion flow of 900 m3/s,the local head loss of the inlet section is 0.246 m.The time-average pressure gradients of inlet pressing pipe segment on the top surface and along the side are small.The maximum height of water surface fluctuations of the access door well and fast gate well is only 0.09 m.So the shape of pressing inlet section is good.The flow rate and distribution characteristics of trash rack section change with the reservoir water level during the unit operation,and the highest gate velocity is about 2.1 m/s.