Investigation Into The Internal Flow Field Of A Canned Motor Pump

Canned motor pumps, as one kind of non-seal pumps, are widely used in the industry because they are leak-free, highly secure and reliable. In this paper, a low vibration canned motor pump is selected as the model to invest the internal flow filed under rated condition using numerical methods. The influence of changing the flow rate and the impeller diameter on the internal flow field, especially the pressure fluctuation, is also explored.The author first introduces some preliminary theory in computational fluid dynamics (CFD), including governing equations, turbulence models, near-wall treatment as well as solution algorithm. Then the modeling and meshing work is accomplished basing on the hydraulic model drawings. By comparing the calculation results of different turbulence models with the experiment, the best setup of the calculation is determined. Through the analysis of simulation results, a preliminary understanding of the distribution of the flow field inside the canned motor pump is acquired, including pressure pulsation generation mechanism and its characteristics, as well as the influence of changing the flow rate and impeller diameter on the pressure pulsation. The results shows that both operations can change the flow field significantly, affecting the pressure fluctuation amplitude at blade passing frequency and its multiplication. However, the amplitude of white noise in the pump does not change much with the two operations. The research of the canned motor pump provides a certain reference for the subsequent optimization of the design in order to reduce the pressure pulsation, as well as vibration and noise control.