| Summary: | 博士 === 國立臺灣大學 === 機械工程學研究所 === 97 === This thesis experimentally and numerically investigates the thermal performance of a 2350 kW completely enclosed motor, which includes a centrifugal fan, two axial fans, a shaft, a rotor, a stator and a stagger heat exchanger with 637 cooling tubes. The motor is cooled through an air to air heat exchanger. The air in the heat exchanger includes external and internal flow paths. The external air driven by the rotation of the centrifugal fan goes through the heat exchanger mounted on the top of the frame. The internal air absorbs heat released from the stator and rotor and then transfers heat to the heat exchanger through the motion of two axial fans and rotor. Several test rigs have been set up in order to measure the performance of fan and motor. Fluent software package is adopted to analyze the complicated thermal-fluid interactions among centrifugal fan, two axial fans, heat exchanger, stator and rotor. The measured data, including fan performance curves and temperature profiles of heat exchanger and stator, show good agreements with the simulated results. The numerical calculations also show that the non-uniform external flow distribution through the heat exchanger and the air leakage between axial fan and rotor reduce the cooling ability of motor. A detail discussion is also made to improve the motor cooling performance. In order to improve the cooling performance of the existing motor, proposed strategies include the new design of centrifugal fan with guide vanes, heat exchanger with different configurations, and optimal distance between axial fan and rotor. The motor integrated with the proposed design methods can decrease the temperature 6 oC in both stator and rotor. In addition, this study builds motor heat dissipation of a new design method, which provides for motor researchers.
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