Study Of Hydraulic Characteristic During Start-up Transition Of Turbular Pumping Station

With the development of industrial and agricultural production and the improving of people's living standards, there are more demanding for water conservancy facilities, in this process, more and more large pumping station have being or will be built in domestic and abroad. There are many types of pumping stations, according to pump type. Tubular pumping station is the pumping station, which is installed with tubular pump to develop low-head water resources. The feature is low head, large flow, The pump unit installations is more efficient; the comparison of overall performance and integrated investment of this pumping station is priorities. At present, with the development of technology of the large and medium tubular turbine and tubular pump, the equipment costs is declined and the shaft stability and ease of maintenance is more improved, so the tubular pumping station has been widely applied in the plain areas. In the largest water diversion project of the century-North Water Transfer Project, it is planned to build 7 tubular pumping stations of the 14 pumping station in Jiangsu Province. In the stable condition, tubular pump generally work well, but at the starting up and the stopping process, the water-mechanical transients would often work in adverse conditions, thereby it will affect the security and reliable operation of the pump system. Because of the characteristics of tubular pumping station, it is often difficult to start to affect the reliability of the pump system as a result of various unfavorable factors.This paper focuses on the transition process of the tubular pump starting characteristics of the various parameters. As the tubular turbulence is short and straight, there is often installed fast gate in the export. In the transition process, the head increases so fast of the speed of the gate that it will lead to motor overload. The purpose of this research is to establish a transition process model between various parameters and their variation, then to take effective measures to improve safety and reliability of plant operation. By the research of this process, it will improve the starting characteristics and the reliability. It is valuable to facilitate the further development of tubular pumping.This article analysis all major conditions experienced by the tubular pump transition process and the main working parameters involved, then combining the starting characteristics of motors and pumps feature to establish the transitional process of the torque balance equation. It is a complex unstable process of the tubular pump start transition, the characteristics are subject to various factors. In this paper, it analyzes the influence of the speed for the opening gate and the delaying time of gates and parapet height and the angles of the impeller blade. The process is divided into several stages by the change of the parapet level due to the opening time of the gate, the upstream water level, parapet roof elevation, the highest water level inside the parapet as the critical point, then analysis the relationship between various parameters and the impact of factors. Treat the characteristics of the motor and pump characteristics as known factor, then establish dynamic model by principles of fluid, take Huaian NO.3 station as an example to calculate. The results show that, in the tubular pump start the process, the delay time of opening gate and the speed of the starting gate are significant influence the transition process. It is propitious to the transition process by delaying the starting time of opening gate and speeding up the speed of opening gate. The starting torque can be reduced by adjust the angle of impeller. The height of parapet has certain influence of the transition process. It can improve the starting characteristics by reducing the height of parapet.