Study On Gas-liquid Two-phase Flow Of The Residual Heat Pump

Residual heat pump is the only kind of secondary pump installed in the containment of nuclear power plant.As an important part of the residual heat removal system of nuclear power plant,it exists in the primary loop system.Its main function is to discharge the residual heat in the system.Its operation stability directly affects the operation safety of nuclear power plant.Due to the complex gas-liquid two-phase flow of the residual heat removal pump during the start-up and exhaust process,the pump head and efficiency will be greatly affected,and the flow characteristics in the pump will be more complex and difficult to capture.Therefore,it is of great significance to study the flow characteristics of residual heat removal pump under gas-liquid two-phase flow conditions for its design and nuclear power plant safety and stability.In this paper,the hydraulic design of the residual heat pump is carried out,and the numerical simulation method is used to calculate the internal flow in the gas-liquid two-phase flow condition.Besides,the flow characteristics of the whole flow field in the residual heat pump are obtained.And the conclusions are as follows:(1)The single-phase steady-state calculation of the designed residual heat pump was carried out,and its external characteristic curve and internal flow field flow law were obtained.At the same time,the external characteristic test of the residual heat pump prototype was carried out to verify the numerical results and the test results showed good matching.(2)Based on the analysis of the mechanism of pressure fluctuation in the pump,the effects of 10%,15%,20% and 30% void fraction on the internal flow field of the residual heat removal pump were studied under three typical flow conditions of 0.8Q,1.0Q and 1.2Q,and the variation characteristics of the external characteristics were obtained.(3)The relative position of the guide vane is defined as ?.Under the design flow rate and four conditions of 10%,15%,20% and 30% void fraction,the influence of different guide vane circumferential placement angles(0,10,20 and 40 degrees)on the internal flow field of the residual heat removal pump is studied.The variation characteristics of the external characteristics are obtained.The dynamic and static interference between the impeller and the guide vane is studied.Under the action of the impeller radial force change law,but also obtained the residual heat removal pump under different air content of the internal flow field characteristics.Through the study on the gas-liquid two-phase flow of residual heat removal pump,this paper aims to reveal the flow characteristics of the pump in the process of operation,especially the complex flow characteristics of gas-liquid mixing in the pump,thus providing a theoretical basis and reference for the design and optimization of residual heat removal pump.At the same time,because this paper only studied the characteristics of the residual heat pump under three flow conditions,the follow-up study can do more research under small flow and large flow conditions,but also can study and analyze the real operating conditions of the residual heat pump under high temperature and high pressure,laying a theoretical foundation for engineering applications.