Numerical Study on the Effect of Influent Flow for Film Pressure in a Helical Grooved Plain Bearing of a Canned Motor Pump

A canned motor pump is a turbopump with a non-seal structure that integrates the pump and the motor into a single unit. A feature of the structure is that the pumped liquid also serves as the cooling liquid for the motor and the lubricating liquid for the sliding surfaces. In canned motor pumps, helical grooved plain bearings are typically used to provide adequate cooling of the motor. The flow rate of the influent flow to this bearing varies with the internal flow of the pump. Therefore, pumps that operate under a variety of conditions require suitable design for the tribological effects of this change in the flow rate of the influent flow, but the details of this design have not yet been clarified. This study focuses on the film pressure, which is important for the design of helical grooved plain bearings for canned motor pumps. The purpose of the study is to determine the effect of this influent flow on the film pressure through numerical analysis using Computational Fluid Dynamics (CFD). The CFD software used was OpenFOAM. Calculations under different conditions were performed to analyze the changes in film pressure that occur in the helical grooved plain bearing. Since the influent flow into the bearing affects the film pressure, it is concluded that the design must take into account the pump internal circulation of the pumped liquid, even from a tribological perspective.