Magnetic-liquid double suspension bearing(MLDSB)is a new type of suspension bearing based on electromagnetic suspension and supplemented by hydrostatic supporting.Without affecting the electromagnetic suspension force...Magnetic-liquid double suspension bearing(MLDSB)is a new type of suspension bearing based on electromagnetic suspension and supplemented by hydrostatic supporting.Without affecting the electromagnetic suspension force,the hydrostatic supporting effect is increased,and the real-time coupling of magnetic and liquid supporting can be realized.However,due to the high rotation speed,the rotor part produces eddy current loss,resulting in a large temperature rise and large ther-mal deformation,which makes the oil film thickness deviate from the initial design.The support and bearing characteristics are seriously affected.Therefore,this paper intends to explore the internal effects of eddy current loss of the rotor on the temperature rise and thermal deformation of MLDSB.Firstly,the 2D magnetic flow coupling mathematical model of MLDSB is established,and the eddy current loss distribution characteristics of the rotor are numerically simulated by Maxwell software.Secondly,the internal influence of mapping relationship of structural operating parameters such as input current,coil turns and rotor speed on rotor eddy current loss is revealed,and the changing trend of rotor eddy current loss under different design parameters is explored.Thirdly,the eddy cur-rent loss is loaded into the heat transfer finite element calculation model as a heat source,and the temperature rise of the rotor and its thermal deformation are simulated and analyzed,and the influ-ence of eddy current loss on rotor temperature rise and thermal deformation is revealed.Finally,the pressure-flow curve and the distribution law of the internal flow field are tested by the particle image velocimetry(PIV)system.The results show that eddy current loss increases linearly with the in-crease of coil current,coil turns and rotor speed.The effect of rotational speed on eddy current loss is much higher than that of coil current and coil turns.The maximum temperature rise,minimum temperature rise and maximum thermal deformation of the rotor increase with the increase of eddy current loss.The test results of flow-pressure and internal trace curves are basically consistent with the theoretical simulation,which effectively verifies the correctness of the theoretical simulation.The research results can provide theoretical basis for the design and safe and stable operation of magnetic fluid double suspension bearings.展开更多
金属氧化物避雷器(MOA)在污秽条件下的内部温升及其热稳定性是研究避雷器耐污能力的重要方面。为此,以GB 11032—2010附录O中的污秽试验方法为基础,同时参考IEEE Std C 62.11—1999,试验比较了不同盐密、不同支架高度等情况下进行人工...金属氧化物避雷器(MOA)在污秽条件下的内部温升及其热稳定性是研究避雷器耐污能力的重要方面。为此,以GB 11032—2010附录O中的污秽试验方法为基础,同时参考IEEE Std C 62.11—1999,试验比较了不同盐密、不同支架高度等情况下进行人工污秽试验时避雷器的内部温升情况,同时还比较了复合外套及瓷外套避雷器的耐污能力及雾湿润条件对避雷器耐污能力的影响等。试验结果表明,仅监测底部阻性电流不能准确反映避雷器的内部热稳定性;考虑雾湿润进行污秽试验时内部温升较高且分散性小。最后提出了一个改进的污秽试验方法,主要增加了雾湿润条件和实时监测内部温度两个条件。展开更多
基金the Natural Science Foundation of Hebei Province(No.E2020203052)the S&T Program of Hebei(No.236Z1901G).
文摘Magnetic-liquid double suspension bearing(MLDSB)is a new type of suspension bearing based on electromagnetic suspension and supplemented by hydrostatic supporting.Without affecting the electromagnetic suspension force,the hydrostatic supporting effect is increased,and the real-time coupling of magnetic and liquid supporting can be realized.However,due to the high rotation speed,the rotor part produces eddy current loss,resulting in a large temperature rise and large ther-mal deformation,which makes the oil film thickness deviate from the initial design.The support and bearing characteristics are seriously affected.Therefore,this paper intends to explore the internal effects of eddy current loss of the rotor on the temperature rise and thermal deformation of MLDSB.Firstly,the 2D magnetic flow coupling mathematical model of MLDSB is established,and the eddy current loss distribution characteristics of the rotor are numerically simulated by Maxwell software.Secondly,the internal influence of mapping relationship of structural operating parameters such as input current,coil turns and rotor speed on rotor eddy current loss is revealed,and the changing trend of rotor eddy current loss under different design parameters is explored.Thirdly,the eddy cur-rent loss is loaded into the heat transfer finite element calculation model as a heat source,and the temperature rise of the rotor and its thermal deformation are simulated and analyzed,and the influ-ence of eddy current loss on rotor temperature rise and thermal deformation is revealed.Finally,the pressure-flow curve and the distribution law of the internal flow field are tested by the particle image velocimetry(PIV)system.The results show that eddy current loss increases linearly with the in-crease of coil current,coil turns and rotor speed.The effect of rotational speed on eddy current loss is much higher than that of coil current and coil turns.The maximum temperature rise,minimum temperature rise and maximum thermal deformation of the rotor increase with the increase of eddy current loss.The test results of flow-pressure and internal trace curves are basically consistent with the theoretical simulation,which effectively verifies the correctness of the theoretical simulation.The research results can provide theoretical basis for the design and safe and stable operation of magnetic fluid double suspension bearings.
文摘金属氧化物避雷器(MOA)在污秽条件下的内部温升及其热稳定性是研究避雷器耐污能力的重要方面。为此,以GB 11032—2010附录O中的污秽试验方法为基础,同时参考IEEE Std C 62.11—1999,试验比较了不同盐密、不同支架高度等情况下进行人工污秽试验时避雷器的内部温升情况,同时还比较了复合外套及瓷外套避雷器的耐污能力及雾湿润条件对避雷器耐污能力的影响等。试验结果表明,仅监测底部阻性电流不能准确反映避雷器的内部热稳定性;考虑雾湿润进行污秽试验时内部温升较高且分散性小。最后提出了一个改进的污秽试验方法,主要增加了雾湿润条件和实时监测内部温度两个条件。
