Research on Heat Transfer Characteristics Based on Thermal‐Fluid Coupling Analysis of the Magnetic Coupler

ABSTRACT Taking the magnetic coupler employed in the power generation device harnessing natural gas pressure energy as the research subject, the heat transfer characteristics of the magnetic coupler and the external flow field under the eddy current effect are exhaustively investigated to address the heating issue caused by that effect. A thermal‐fluid coupling model for the magnetic coupler and its flow field is established. With the eddy current loss on the isolation sleeve regarded as the heat source, the temperature distribution characteristics of each component of the magnetic coupler under the rated operating conditions are simulated. The flow state around the magnetic coupler and the heat transfer features on the outer wall of the isolation sleeve are further analyzed. To address the issues that the air in the gap has difficulty circulating along the axial direction and the temperature of the internal magnets is close to the maximum allowable working temperature, the heat dissipation structure of the magnetic coupler is enhanced by modifying the eccentric distance, increasing the quantity and the diameter of the heat dissipation holes on the external rotor. Eventually, the maximum convective heat transfer coefficient of the outer wall surface of the isolation sleeve is raised from 23.6 W/(m 2 °C) to 61.7 W/(m 2 °C), and the temperature of the internal magnet is kept below 50.9°C, attaining a favorable heat dissipation effect and meeting the usage requirements.