Research on the clearance flow between stator and rotor cans in canned motor RCP

Abstract

Canned motor reactor coolant pump (canned motor RCP) is the only long-term continuously running kernel equipment in the reactor system, the safety and stability of the canned motor RCP is the guarantee of the reactor security. In the usual working condition, the auxiliary impeller drives the primary cooling water flow upward into the clearance between the stator and rotor cans to bring the heat produced by the motor, forming a clearance flow with axial temperature gradient. A coupling analysis method is presented to study temperature field of the canned motor and the influence of viscosity temperature effect on clearance flow. The results indicate temperature at outlet of the clearance between stator and rotor cans is about 10 degrees higher than the inlet. What’s more, the differences of results with dynamic viscosity defines as quadratic fitting and results with dynamic viscosity defines at average clearance temperature are less than 1%. As to design method of the clearance, electromagnetic conversion efficiency and starting torque, motor cooling performance and stability of rotor system should be comprehensively considered in the clearance design process.