Numerical Analysis of Rotordynamic Coefficients of Annular Flow in Canned Motor RCP

The operating performance and safety characteristics of canned motor Reactor Coolant Pump (RCP) are vital to the nuclear reactor. The annular flow, which is between the rotor and stator, makes substantial effects on the rotordynamic characteristics of RCP. In this work, the annular flow is simulated by means of 3-dimensional CFD approaches. The annular flow field and the auxiliary impeller are modeled. The results show that the pre-swirl strength at the inlet of the annular flow is evident. Another model without the auxiliary impeller is analyzed under constant pre-swirl ratio with various axial flow rates and whirl speeds. The rotordynamic coefficients of the annular flow are obtained. The results are compared with theoretical predictions. Numerical results show that the fluid in the annular region makes remarkable effects on the rotordynamic characteristics of the canned motor RCP.