Study On Simplification Simulation Of Water Supply Network Based On Cut-off Water Hammer Model

The construction of water supply network is an important livelihood project related to urban development,and its operation directly affects the residents' normal life.Water hammer analysis of water supply network is one of the most important means to ensure the safety of the network.However,the current study on water hammer is mostly concentrated in single pipe or pipeline with a small number of branches,and the study on water hammer in circular water supply network is still lagging behind.Moreover,the water supply network has gradually become huge and complex.Without simplification,the amount of calculation will increase by geometric multiples,which makes it difficult to apply to practical projects.Therefore,the study on the influence of pipeline simplification on the hydraulic transient calculation of water distribution network is an effective method to solve the high-efficiency water hammer analysis of water distribution network,which is of great significance for ensuring the safe operation of water distribution network.Firstly,this paper briefly introduced the basic theory and method of water hammer analysis in water supply network.Aiming at the characteristics of water supply network,the boundary conditions needed in the process of water hammer analysis were supplemented and deduced,and the rationality of simulation results based on cut-off water hammer model was verified by relevant experimental data.Secondly,this paper combined two specific examples to discuss the influence of water distribution branch simplification on water hammer analysis of water distribution network.Two different simplification methods were proposed and simulated by using the cut-off water hammer model.The results showed that:(1)When the diameter ratio of water distribution branch pipe to main pipe was below 0.125,the direct removal of water distribution branch pipe had no significant effect on its hydraulic transient calculation results;(2)In view of the large number of water distribution branch pipe and the close distance,the simplified model calculation accuracy by hydraulic equivalent method was obviously better than that by direct removal method.Thirdly,a practical water distribution network was pretreated by using the above conclusions about the simplification of water distribution branch pipe.The influence of the simplification of annular water distribution pipe on the water hammer analysis of water distribution network was discussed by using the treated water distribution network.Two different simplification methods were proposed and simulated by using the cut-off water hammer model.The results showed that:(1)The simplified hydraulic equivalent method was superior to the direct removal method in calculating the model accuracy of the annular distribution pipe;(2)The hydraulic equivalent method was employed to simplify the annular distribution pipe,if the degree of simplification was relatively large,it would also had a greater impact on the hydraulic transient calculation results of the network.Finally,the water hammer protection of the water supply network before and after simplification was checked.According to the results,it was found that the simplification of the water supply network to a certain extent will not affect its water hammer protection design.These results also confirmed the feasibility of using pipeline simplification to analyze the water hammer of water supply network with high efficiency,and provided a reference for future related research.