Research On Fluid Transient In Water Hydraulic Pipeline Based On Method Of Characteristics

Nowadays,haze is happening frequently and environmental pollution is serious.Therefore environmental protection is becoming more and more important in social development.Pure water hydraulic technology has been more and more widely used in in industrial production and life as a new green technology.Due to the physical and chemical properties of pure water,various problems arise when pure water hydraulic equipment is used and designed.Water hammer is one of important problems that can't be ignored in pure water hydraulic pipes.Water hammer makes a huge pressure shock,vibration,noise and even leads to cavitation and cavitation erosion,which affects normal functions of pumps,valves,pipes and other hydraulic components and reduces service life of the entire hydraulic system in pure water hydraulic system.In this paper,the study of transient process of water hammer in pure water hydraulic pipeline is performed by simulating and experimenting.The main research contents are as follows:1.The transient process of pure water hydraulic pipeline is analyzed,and the unsteady flow wave equations and the friction model and the cavitation model are derived.Then,partial differential equation of the pipeline transient process is transformed into total differential equation by the method of characteristic;2.The processes of the upstream and downstream models of pure water hydraulic pipeline are analyzed,and make used of the method of characteristic to simulate and predict upstream transient process of the high and low pressure pipeline and downstream transient process of the high and low pressure pipeline.Then,compare simulation results with test results.At the same time,the cavitation in pure water hydraulic pipeline during the transient process is predicted;3.Pure water hydraulic upstream and downstream pipeline model is built and add a controllable valve in order to study the valve-closing time and the maximum pressure peak relationship during transient process in AMESim.It can provides some academic bases and references in designing valve and control valve-closing time the in the pure water hydraulic test bench,avoiding and take advantage of the maximum pressure peak in application;4.The influences of temperature,initial gas content and flow rate during the downstream transient process are studied in low pressure pure water hydraulic pipeline by using pure water hydraulic test bench,and the characteristics of pressure pulsation are analyzed;This paper studies transient process in pure water hydraulic pipeline by simulation and test methods.The method of characteristics is used to predict the transient process in pure water hydraulic pipeline.At the same time,transient process in pure water hydraulic pipeline is studied by experiment.Through the comparison of the experimental results and the simulation results,the method of characteristics is used to predict transient process in low and high pressure pure water hydraulic pipeline well.