CAP1400反应堆冷却剂系统中蒸汽发生器下封头和核主泵直接连接,使蒸汽发生器下封头出口接管的流场变得不均匀.为探究非均匀入流条件对核主泵性能的影响,对核主泵叶轮和蒸汽发生器下封头进行联合简化建模,采用CFD方法数值计算泵的能量、水动力以及空化性能,并与均匀入流下的仿真结果进行比较.计算结果表明:在0.7Q0～1.2Q0工况范围内,进口的不均匀流动导致泵的扬程下降1.8％～5.1％,叶轮扭矩下降1.9％～6.4％,而效率没有发生明显的变化;非均匀入流下扬程的降低使叶轮所受轴向力有所减小,但径向力显著增大.空化发生时,泵的临界空化余量增大,抗空化性能降低,空化区域出现明显的不对称.%Reactor coolant pump (RCP )of CAP1400 reactor coolant system is designed welded directly to the steam generator (SG)channel head,which makes the flow field in the SG channel head outlet nozzle non-uniform. To study the influence of inflow distortion on RCP performances, comparisons of energy, hydrodynamics and cavitation characteristics between non-uniform and uniform inflow conditions are carried out by CFD method through modelling integrally the channel head of SG and RCP impellers.Calculation results show that at 0.7Q0-1.2Q0 the inflow distortion reduces pump head and impeller torque by 1.8％-5.1％ and 1.9％-6.4％ respectively,and efficiency is not affected.With the decrease of head,axial loading drops slightly whereas radial loading increases significantly under non-uniform suction flow.As cavitation occurs,the critical NPSH of the pump increases,anti-cavitation performance is reduced and cavitation area appears obvious asymmetric.
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