Study On Hydraulic Control Of The Open Channel Water Diversion System In The Water Transfer Project

Open-channel water diversion system in the water transfer project is an extremely complicated system which is made up of a long distance main canal and several check gates and diversion sluices and so on. Due to series of factors such as the long distance canal system, multiple buildings and wide distribution, it's hard to control the hydraulic dispatch for uninterrupted water supply. Under normal operating conditions and abnormal operating conditions (accident, water pollution and canal damage), If it controlled inappropriately, it will lead to dam slide and threat the stability of the canal slope and liner. Besides, it will cause various complicated hydraulic phenomena (the phenomena of hydraulic oscillation and gravity channel). For ensuring the canal water conveyance system to adapt to the change of flow quickly, implementing water supply safely, timely and suitably, it need to make further research on the hydraulic control.Take the canal-head segment of Middle-line Scheme of Water Transfer Project from South to North China as example, this essay mainly researches on the canal hydraulic control by establishing unsteady mathematic model and making numerical simulation. The research includes the following aspects:(1)Downstream constant level control method and mid point constant level control method are analyzed and compared by storage amount of the steady flow, water level fluctuation and stable time which generated in the process of unsteady flow and the engineering amounts.(2) Study on the influence of check sluice's open-close mechanism on the hydraulic characteristics of the water delivery system.(3) Analyze the theory and hydraulic characteristics of the gravity channel and water alternative lift phenomena which caused by suddenly closing of two adjacent check sluice in the channel hydraulic pipeline.(4) Study on the influences of different controlling gate intervals on the response time and raising water level when discharge changes, eliminating accident time and investment ratio of gate building in the water transportation open channel and advice that the optimal controlling gate interval is 25-35km, which can guide controlling gate interval's design and safety running of the sluice in practical engineering.(5) Study on the combined control of check sluice in the long-distance and open-canal water delivery system. The synchronous control method and the sequential control method are compared by analyzing the hydraulic characteristics. Based on results, while the discharge enlarged, sequential control method is suggested to use; while the flow of downstream need to reduce immediately for unexpected situations, synchronous control method is suggested to use.