The Computation Research On The Model Of Suddenly Pump-stopping Hammer In The Single Water Source Urban Water Supply Pipe Network

In recent years, the urbanization and new urbanization construction in our country have developed rapidly under the leader of important thought of “Chinese Dream”. At the same time, the urban pipeline engineering in our country implements a leap type development,there’s more Water Treatment Plants, the distance of water is disported farther and farther, the structure of the urban pipe network getting more and more complicated. The most of the urban pipeline in our country built in the 1970 s, the pipe network is so old as to leak seriously, and the pipe-bursting accident occurs frequently. Therefore,more and more cities reformed its old pipe network gradually. How to reform the old pipe network economically and reasonably, and how to ensure the safety of water for life and process water, which become one of the problems need to be solved in today’s society. Water hammer is one of the key factors threatened the security of urban water supply pipeline, which can’t be ignored in the design of the pipe network construction and retrofit, and which is also known as one of the difficult technical problems needed to be resolved in the pipe network design theory. At present, water hammer theory research of pump station has been matured, and the research on calculation of the model has been increasingly deepening. However, the study on calculation of water hammer in urban water supply pipe network is very little. The study will be based on the research achievement of the transient flow theory; the key point of the research will be focused on calculation of the model of water hammer of cavities collapsing. The thesis mainly complete the content is as follows:1. The paper minutely elaborated the fundamental principle of calculation of water hammer and the differential equation of water hammer which is suitable for computer calculation based on the theory of gas-liquid two phases flow.2. In this paper, combined with the characteristics of urban pipe network,the author established the hydraulic calculation model of branch pipe nodes. What’s more, the thesis established two mathematical models, which was the cutoff water hammer and the non-cutoff water hammer due to power failure.3. The most of the designer only calculate and protect the water hammer in water supply pipe network under design condition. The author thought which is unreasonable, and the average condition and the low flow rate condition should also be the analysis condition as the design condition when conducting water hammer calculation and protection. And the thesis formulated the reasonable water hammer calculation and analysis methods.4. This paper briefly established the process of drawing up the program which is used to calculate hydraulic transition process of water supply pipe network with single water source.5. Combined with engineering examples, write and run the MATLAB program of different working conditions which is designed for calculating suddenly pump-stopping hammer in the single water source urban water supply pipe network. In the process of choosing the best scheme, this paper expounded the process of protection design of water hammer happened in actual water supply pipe network, and the optimal water hammer protection scheme of the engineering example is given at last.