Stratified Water Power Station Water Hydraulic Characteristics Of The Numerical Simulation Study

As the need for water ecological protection, some hydropower stations havestarted to adopt Multi-Level Intake Structures (MLIS). MLIS permits to withdrawsurface warm water from the reservoir and effectively reduce the negative effectof releasing cold water on the downstream water ecological environment, so as tosatisfy the related environmental design requirements. However, reducing the crosssection area will worsen the flow condition in intake structures, and the headloss will increase, so that the operation safety and generation efficiency areaffected. Therefore, it's meaningful to study on the hydraulic characteristicsof multi-level intake structures and optimize the body feature parameters so asto ensure safe and efficient operation.Based on the Tingzikou Dam on Jialing River, the rigid boundaries of MLIS withstoplog gate are simulated accurately with hexahedral structured grids, and thehydraulic characteristics including velocity distribution, head loss and time meanpressure distribution are studied. Besides, the results gained from mathematicsmodel are also verified by physical model test results. Studies indicate that:(1)Flow field structures of power station intake with stoplog gate aresimulated reasonably by mathematical model, which provides powerful supports ofassessments for the impact on the hydraulic characteristics, such as flow pattern,head loss, pressure and so on.(2)After setting Stoplog gate, the coefficients of head loss of intakeincreased to a varying degree when compared with non-Stoplog gate. Under certainsubmergence depth condition, there was a critical value of the ratio of Stoplogheight and bell mouth intake height d/D. When this critical value was exceeded,the amplitude of head loss coefficient would be significantly increased. Criticalvalue of d/D would increase as the submergence depth increased.(3)After setting Stoplog gate, vertical vortex would appear at the end of trash rack pier, whose harmfulness was concerned with flow pattern parameterλλ). For the intakes of Tingzikou Dam, harmful flow pattern wouldnot appear whenλ≤6.99×10-3, but would appear when the critical value ofλwasbetween 6.99×10-3 and 15.7×10-3.(4)Numerical simulation method and results used in this paper can be takenas similar projects'reference.