Research of cavitation characteristics of RCP based on section-constrained blades

Abstract

To make sure that the bubbles will not block the impeller passage in the process of the transient cavitation, a section-constrained design is adopted in the hydraulic design of the CAP1400 Reactor Coolant Pump’s(RCP’s) impeller blade, and the cavitation bubble distribution on the suction side of the blade in the CAP1400 RCP under the transient cavitation condition and the internal pressure pulsation are studied. To study the performance of the section-constrained impeller blade, simulations are carried out by using the CFX software, the cavitation bubble distribution on the suction side and the pulsation dynamics at each monitoring point in different extents of cavitation are obtained based on the Reynolds-averaged N-S equation and the SST k - ω equation. The results show that the section-constrained blade has a good constraint capacity on the cavitation, and could enhance the passing ability of the blade in some extent. The main causes of the pressure pulsation inside a pump are the rotor-stator interaction, the separated flow at the round-like pump chamber, and the reflux inside the flow passage. The pressure pulsation inside the impeller and the guide vane is characterized by the significant periodicity, which are both affected by the rotor-stator interaction. And the impeller outlet and the guide vane inlet are more susceptible to the rotor-stator interaction. Studies of the vapor-liquid two-phase flow and the pressure pulsation inside the RCP’s impeller with the transient cavitation are of great significance for the prediction of the RCP’s dynamic characteristics after the cavitation, and for the safety and the stable running of the RCP.