Investigation of the self-balance impeller of a canned motor pump for axial force reduction

Abstract

Canned motor pump is widely used in the transportation of chemical industry. The common failure component of the pump is the sliding bearing. The service life of the bearing will be directly reduced if it bears too much axial force. Thus, it has higher requirements on the axial force balance of the impeller. In this study, the axial force and the axial force self-balance position of the canned motor pump impeller were calculated and analyzed by numerical calculation and experimental verification. By deducing the theoretical formula of the clearance, the relationship between the total axial force of the impeller and the size of the axial clearance is obtained, which can be concluded simply to a functional equation. Based on the principle of curve fitting, an iterative asymptotic strategy is proposed to solve the self-balance position. This method successfully avoids the problem that the axial clearance falls into “solving interval traps.” The results show that the axial force is sensitive to axial clearance at a special interval. The axial clearance size decreases with the flow rate increasing. This study is of great significance for solving the axial force balance state of impeller.