Study on internal flow characteristics of reactor coolant pump under non-uniform inflow

Abstract

This study explored the complexity of internal flow patterns in a reactor coolant pump (RCP) facing non-uniform inflow conditions. Utilizing CFD simulations, we analyzed the flow behavior under non-uniform inlet conditions simulated by a steam generator and compared it with flows under standard straight pipe inlets. The examination covered five main computational areas: the inlet, the rotating impeller, the stationary diffuser, the casing, and the outlet extension. By examining the transient evolution of the pump's primary flow components under varying inflow conditions, the study exposed the impact of non-uniform inflow on the pump's internal flow field. It was observed that non-uniform inflow, particularly under the simulated conditions of the steam generator, significantly influences the velocity and pressure distributions within the impeller and diffuser, consequently affecting the pump's performance by reducing flow stability and energy conversion efficiency. Additionally, the study established grid independence, ensuring the accuracy and reliability of the numerical simulation results. These findings offer vital scientific insights for the design and operation of RCPs and enhance the prediction and optimization of real pump performance through precise flow field simulations that reflect actual inflow conditions.