Impact Of Diffuser Width On The Performance Of AP1000 Reactor Coolant Pump

For the problem of incapable to determine the width of spherical diffuser, four groups of spherial diffusers with different width were designed by using the speed coefficient method. Numerical investigation of internal flow in the nuclear coolant pumps with these diffusers was made based on ANSYS-CFX software. Aimed at the efficiency, ditribution of pressure and velocity vector on the meridian plane of each volute scheme was analysised emphatically. By comparing the performance curves of the coolant pumps predicted by the numerical simulation, we can draw that the head and efficiency of pump decreased as the increasing of diffuser width and performanced worst at the width of d=1.7R, then the performance no longer changes when diffuser width continue to reduce.