Numerical Study On Hydraulic Characteristics Of Multi-level Intakes Of Hydropower Stations

To control or eliminate the adverse impact on water environment of downstreamriver of cold water discharged by hydroelectric power generation, multi-level intakeshas been recommended as a typical measure. Compared with the traditionalsingle-level inlet, multi-level intakes decreased water flow area, inflated importelevation, the flow pattern is more complicated. In the design of water intakes, Itshould be ensured that the flow is smooth and steady, and the head loss should bereduced as much as possible. Therefore, study on hydraulic characteristics ofmulti-level intakes and optimizing of inlet size parameters has important significanceensuring safe and efficient operation of power stations.This paper selected Nuozhadu hydropower station, Jinping first stage hydropowerstation and Guangzhao hydropower station as our study sample, and studied thehydraulic characteristics of multi-level intakes of hydropower stations numerically bya3D k turbulent model. Through the analysis and summary of the resultsobtained, we obtained certain rules for the future multi-inlet design reference.First of all, the head loss of physical model experiment results and numericalstudy results of Nuo Zhadu hydropower station is compared, the results showed greatagreement. Indicating that the results got from this method can study the hydrauliccharacteristics of the multi-level intakes authenticly. Then the hydrauliccharacteristics of multi-level intakes of Nuozhadu hydropower station, Jinping firststage hydropower station and Guangzhao hydropower station were studied by thismethod. The difference between their head loss were analyzed. No stoplog retainingwater working condition, the flow state of the intakes of Nuozhadu hydropowerstation and Jinping first stage hydropower station is stable, while it is unstable inGuangzhao hydropower station. This is mainly because of the larger size of stoplogpier of Guangzhao hydropower station. Stoplog retaining water working condition,recirculation zone occurred in downstream water intake chambers of Nuozhaduhydropower station and Jinping first stage hydropower station. Guangzhaohydropower station situation is better for the water chamber width is reasonablyarranged. Velocity in front of the intake is higher within the height range of stoplog topelevation, illustrates the use of multi-level inlet can effectively achieve the sake ofselective access to different water layers of the reservoir and has a positive protectiveeffect to the downstream environment.The research achievement can guide the designof related projects.