Hydraulic Model Test Research On The Pump System、Water Supply＆Electrical Power Generating System Of San He Kou Water Conservancy

Hanjiang-to-weihe Water Transfer Project is a large-scale interbasin water transferproject which can solve the problem of water shortage in Shaanxi guanzhong region,implement the optimal allocation of water resource, improve the ecological environment andpromote economic development of Shaanxi Province. Huang Jinxia project built at HanjiangRiver and San Hekou reservoir built at Ziwu River is the water supply source of the project.The project supplies water by pumping water from Huang Jinxia pump station, conveyingwater by Huangjinxia-to-Sanhekou tunnel, and then flowing automatically to guanzhong areaby Qinling tunnel. San Hekou project is the regulation and storage central ofHanjiang-to-weihe Water Transfer Project, bearing pumping, water supply, power generationetc. and the running boundary conditions are extremely complex, so it is very important forproject construction and safe operation to improve and optimize the original design schemethrough physical model tests.The pumping and power system in Sanhekou project consists of water inlet, pressurepipelines, bidirectional set powerhouse, water supply pipelines and valve chamber, tailrace,connecting tunnel, control gate chambers and other components. The model designs as gravitysimilarity criterion, and the objects of model test is, analyzing and evaluating the overalllayout plan of project pumping, water supply, power generation system from the perspectiveof hydraulics through the model test, studying the flow pattern in the runner system indifferent conditions such as pumping, power generation, water supply, and the impact on theflow pattern by the hydraulic building in different conditions, analyzing the inlet and outletflow pattern, putting forward building shape optimization schemes and operating conditionsof the control gate; verifying the final running water levels of the control gate, connectingtunnel and tailrace tunnel in all conditions, and determining design water level of the watersupply, pumping, power generation; in addition, studying the tail water level changes attailrace tunnel shaft under the condition of sudden load rejection and load increase ofpumping and generating, in order to guaranteeing tailrace tunnel shaft safety from the rise andfall of the tail water in the special conditions.Based on model test observation and study, some conclusions are concluded as follows: 1)the overall layout scheme of pumping, water supply, power generation systems isreasonable, flow pattern in water pipelines and water conveyance tunnel is well;2) gaseseasily go into the diversion penstocks and tailrace tunnel reconstructed by diversion tunnel toform gas bubbles when water are filled in, so the water filling process should be slow as far aspossible in the prototype;3) on the condition of pumping, when the discharges fromHuang-san tunnel is small, it should raise water level by control gate of Qinling tunnelchamber to meet the designed pumping discharge, and the critical discharge from theHuang-san tunnel corresponded to different pumping discharge is observed by the test whenthe gate of Qinling tunnel chamber is free of controlling;4)when the largest water supplydischarge of San Hekou is70m~3/s, water level in the vertical tailrace tunnel of is higher thanthe highest designed water level of the connecting tunnel. The air height in the verticaltailrace tunnel does not meet the designed requirement, so it should increase the top elevationof the tailrace tunnel to meet the requirement of the air height in connecting tunnel;5) on thecondition of pumping and generating, when bidirectional sets or four generator sets suddenlystart pumping/turn off, or load rejection and load increase, water level falling or rising in thevertical tailrace tunnel is relatively stable, and there is no swells.