Scaling Effect for Hydraulic Performance Prediction of Nuclear Main Pump

In order to improve the hydraulic performance of the nuclear main pump and achieve optimal matching with shielded motor, based on the scaling model conversion algorithm, selecting RNG k-ε turbulence model and SIMPLEC algorithm, unsteady numerical predictions and external characteristic experiments were conducted. The results show that on the flow conditions of 0.4Q_d-0.7Q_d, the head-flow curves are relatively flat; on the rated condition, the predicted value of head is 5% higher than the rated one; the maximum head of the impeller is at the 0.4Q_d operating point, the maximum value of hydraulic efficiency is located at the 0.9Q_d operating point, the simulation value of hydraulic efficiency of the impeller is 5% higher than the experimental one. On small flow rate conditions, the hydraulic loss of guide vane yields the normal distribution law taking the 0.4Q_d condition as the central axis, the maximum value of guide vane hydraulic loss is at the 0.4Q_d operating point. On large flow rate conditions, the minimum hydraulic loss value of the guide vane is at the 1.1Q_d operating point. The hydraulic loss of water pressure chamber is in accordance with sinusoidal distribution law; the peak is located at the vicinity of 0.4Q_d operating point and the trough is near the 0.9Q_d operating point.