| With the development of economy and society in China,more and more large-scale pump stations of pipeline water conveyance projects have been constructed,which play an important role in solving the uneven distribution of water resources in spatio-temporal problem.However,due to external factors such as valve opening and closing,unit start-up and accidental pump stop during the hydraulic transition,the water flow inside the pipeline will change,accompanying with rapid pressure changes inside the pipeline.In severe cases,burst of pipeline and damage to the unit may occour,even lead to flooding pumping station endanger the safety of life and property.Therefore,it is of great significance to ensure the safety of pumping station of pipeline water conveyance project by theoretically analyzing about the hydraulic transition process and taking proper engineering and non-engineering protective measures.Furthermore,considering the large number of parameters that affect the pressure changes in the pipeline during the hydraulic transition,the sensitivity of different parameters of the hydraulic transition calculation model to the output results were analyzed,and the influence of different parameters of the model on the water hammer pressure can be identified,of which the method can be a useful reference by engineering designers.In this paper,Wohushan reservoirs cascade pump station of water conveyance project in Ji'nan City as the research background.Based on the method of characteristics,pump station accidental pumping-stop unfavorable conditions,gravity flow water delivery conditions were simulated and corresponding control and protection measures were taken.Further more,the method of local and global sensitivity analysis were used to analyze the sensitivity of parameters affecting hydraulic transition calculation model of pipeline water conveyance project.Mainly from the following aspects:(1)Study on water hammer protection against accidental pumping-stop of single-stage pumping station in cascade pumping stations.Through the simulation analysis of the most unfavorable working conditions of single-stage pump station,it is put forward that with the air valve and water hammer relief valve and two-stage shut-off valve back the pump along the pipeline can prevent the pressure does not exceed the design pressure value,pump unit does not occur high reversal speed.(2)Research on the coordination and protection of interstage water level for accidental pumping-stop in cascade pumping station.Representative and different pump stations of accidental pumping-stop combination scenarios were simulated and analyzed,in order to prevent the pool overhang or drained,pump operation response time and pump stop sequence of other pump stations in dififerent scenarios were studied.(3)The pipeline gravity water delivery scheme in which the regulation tank is connected with the main pipe in the form of branch was research.Based on the characteristics of project,the different on-off valve timing,connection between main pipe and regulating tank was studied,and different water conveyance schemes were used to make simulation comparative analysis.The water conveyance protection scheme of water flow control valve was put forward.(4)Based on the basic differential equation of water hammer calculation,local and global sensitivity analysis of pipeline hydraulic transition model was carried out.On the analysis of the basic equations of momentum and continuity of pipeline transients,seven main parameters that affec the output of hydraulic transient model were selected.The hydraulic transition models of pipeline was calculated respectively based on modified Morris method and partial correlation analysis to do local and global parameter sensitivity analysis research,and also the analysis of the results were compared.The results show that the three main parameters influencing the hydraulic transient model are the pipe diameter,water flow and valve closing time,and the rationality of the result is analyzed theoretically. |
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