| The current status of one point, such as pressure, flow rate and flow do n t change with time, intitules as the steady flow.If the current status change with time, intitules as the unsteady flow.In the actual projects, because of flow adjusting,accidents or other causation, caused the condition of steady flow is destroyed in the long-distance water supply system, and then the unsteady flow occurs in the system, this phenomenon known as hydraulic transient process.When the hydraulic transient process occurs,the hydraulic parameters in the transient process will change quickly with time and usually overstep the design value of steady flow, which will cause a negative efect on the system. Therefore, researches on the hydraulic transient process is necessary to design and operation of the water transfer system. Especially in the pressure water supply pipe, because of the dramatic changes in flow rate,it will lead to internal fluid pressure to produce rapid alternating movements resulting the water hammer. If not handled properly, the system will lead to a strong vibration of pipeline, pipes seriously deformed or even burst. Therefore, research on the hydraulic transient process, do some necessary calculation of the system security, it is very necessary for the water supply project design and safe operation. This paper bases on the former studies theories, expounds the basic unsteady flow theory and its method of calculating systematically. Method of characteristics is applied to establish the model of open channel unsteady flow calculation, as well as the valve closing water hammer calculation model under gravity flow by different protective measures, it also selects a reasonable numerical calculation method, developes the computer analysis system of the hydraulic transient process. This paper combines the WanJiaZhai Yellow River Diversion North Route Project, gives the numerical calculation and theoretical analysis of the hydraulic transient process. While seeking for the uniform solution to hydraulic transient process, the thesis also brings forward corresponding proofs and suggestions for project design and operation. The researches made by this thesis include several aspects as below:(1) Based on generalizing predecessor research achievement, systemic formulation the basic principle of unsteady flow and method of characteristic curves, present the initial and boundary condition of open channel unsteady flow calculation and the valve closing water hammer calculation,analyzing operating principle of different water hammer protection measure (such as Sleeve valve,Piston valve,air inlet and vent valve, etc.) and their applying conditions.(2) Combined the 1# tunnel of WanJiaZhai Yellow River Diversion North Route Project of ShanXi Province. Based on the Numerical simulation modle, use the computer to simulate system running, analysis different status under different flow(the last flow,the design flow and the minimum flow), provide technical basis for the rational design and security an efficient operation of the water supply system.(3) Combined the 2# inverted siphon of WanJiaZhai Yellow River Diversion North Route Project of ShanXi Province, analysis and calculate the valve closing water hammer under gravity flow, use the method of characteristics combined with valves boundary condition equations, establish a hydraulic calculation model,use the computer to simulate system running, analysis the water hummer protect measures of piston valve. Then it proposes technical basis for the rational design and security an efficient operation of the water supply system. Then it proposes the optimal protection way under the condition of safe operation of the gravity flow inverted siphon water supply system.(4) Adopting Visual Basic 6.0 to exploit good interface, high interactive, credibility performance and simple operating computer numeric simulated system that is applied in the open channel unsteady flow calculation, as well as the valve closing water hammer calculation under gravity flow(5) At the end of the paper, carrying through analysis to the calculation result mentioned above, studying on calculation error's reason, at the same time, putting the further research problem that is existence in the calculation of hydraulic transient process in water supply projects.
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