Improvement And Solution Of Water Hammer Calculation Method For Homogeneous Circular Pipe

Water hammer phenomenon is a common phenomenon of unsteady flow in pressurized water pipeline.Water hammer phenomenon usually damages the water transmission pipeline,and even causes the failure of pump or valve,which has become one of the important factors affecting the safety of pressure water transmission pipeline.Related scholars have studied the phenomenon of water hammering since more than one hundred years ago,but the classical water hammering theory is still worth improving.Therefore,this paper discusses the improvement and solution of water hammer calculation method for homogeneous circular pipe.The main contents and innovative research work are as follows:(1)The classical water hammer theory is introduced in detail.At the same time,the basic differential equations of one-dimensional unsteady flow are deduced,and the merits of improvement of the traditional water hammer theory are proposed.(2)The inhomogeneous body established by the finite control body moving with the fluid is selected,and the equations of motion and continuity are rederived by using the momentum theorem and the law of conservation of mass.The newly derived equations of motion and continuity,the liquid elastic equation and the pipe wall elastic equation are combined to form the new closed equations of water impingement calculation.(3)The comparison between the traditional water hammer calculation equation and the improved water hammer calculation equation is made through a simulation example to verify that the numerical calculation results of the improved water hammer calculation equation are closer to the actual situation,but there is still a gap.Therefore,this paper will transform the improved water hammer calculation equations formally.On the selection of numerical calculation method,because of the characteristic line method used on the mathematical model is too trival,this paper plans to choose difference method for calculation,the boundary conditions and initial conditions are given respectively,establish difference equation,through programming on MATLAB platform and numerical calculation,the calculation of water hammer pressure of end sections are obtained as a result.And draw the pressure with the time of the change of the law curve.By comparing the results with the corresponding numerical results of the classical water hammer calculation theory,it can be seen that the numerical simulation results of the water hammer calculation equations in the transformed form are more consistent with the actual situation,and the water hammer pressure attenuation rate is good.(4)Based on the App Design function of MATLAB,the water hammering simulation program was prepared,and the simulation results were compared with the relevant test results,The simulation results proved that the water hammering simulation program obtained should have certain water hammering simulation ability and reliability.