Study On The Gas-flow And Heat-transfer In The Wedge-shaped Air-gap Of Horizontal Evaporation Cooling Motor

Gas-flow and heat-transfer in the wedge-shape air-gap of horizontal evaporation cooling motor is studied by numerical method and experiment.Under the assumption that the inner surface of stator sleeve and outer surface of rotor are smooth, taking the fact into account that the temperature of stator sleeve of evaporation cooling motor keeps almost the same, horizontal evaporation cooling motor is simplified as a physical model of two coaxial sleeves, with outer sleeve (the stator) holds still and keep at constant temperature and inner sleeve (the rotor) is rotating and heated. The gas-flow in the annular cross section is study, and it is clarified that in such a physical model when rotor is rotating at high speed, the nature-flow is restrained by rotating-flow, so the actual 3D gas-flow field in the wedge-shape air-gap can be simplified to an axial symmetric quasi-3D gas-flow field. With this axial symmetric quasi-3D model, the gas-flow field in such a wedge-shape air-gap is studied, the phenomena about Taylor vortex in such a narrow wedge-shape air-gap is illuminated and the so caused gas-flow in axial direction is explained. The heat-transfer calculation proves that this axial direction gas-flow can do good to the rotor heat-emitting. When the rotating speed of rotor increases, the quantity of the axial gas-flow increases two. But when the heat load of rotor increases, the ratio of the heat bring by the axial direction gas-flow to the total heat load decreases. Under the condition mention in this physical model, when there is a high rotor heat load, the effect of the axial direction gas-flow to the total heat-emitting capability is not very great.An experiment instrument of horizontal evaporation cooling motor with the same dimension such the calculation model is designed and established. The distribution of the gas-flow speed is measured at a position 1cm away from the outlet (the end with larger air-gap). It is illustrated that the gas-flow speed keeps increasing from the out surface of the inner sleeve to the inner surface of the outer sleeve, and then it decreases gradually.This trend is the same as the calculation result. The error between the experiment result and calculation is discussed.At the end of this thesis, some suggestion is mentioned for future research work.