To study the influence laws of different levels of eddy current braking on rail temperature rise,based on the principle of linear eddy current braking,the theoretical formulae of eddy current braking force and rail temperature rise are derived using the law of energy conservation and the skin effect formula of conductors,with the combination of the data of braking force test and heat transfer theory.According to the theoretical formulae,the finite element method is used to establish a rail temperature rise model,and the temperature variation of different parts of the rail after a train applies emergency eddy current braking are analyzed.According to the minimum time interval between the designed train and the current train in operation of Beijing-Shanghai high-speed railway,the rail temperature variation of multiple trains under repeated eddy current braking is calculated,respectively.The results show that using the law of energy conservation to derive the theoretical formulae for eddy current braking force and the rail temperature rise not only ensures the calculation accuracy,but also simplifies the calculation process.After emergency braking of a train,the temperature rise at the top of the rail is the highest,while the temperature changes at the waist and the bottom of the rail are minimal during the braking process.When multiple trains repeatedly apply eddy current braking in the same section,the higher the braking level,the shorter the train interval,and the greater the cumulative temperature rise of rail.When the maximum service braking is repeatedly applied under the condition of minimum train interval,the maximum rail temperature rise meets the requirements of relevant standards for line maintenance.

利用Flux电磁仿真软件建立某高悬挂磁轨制动器有限元模型,研究磁轨制动器极靴在不同磨耗条件下的吸力特性.在不同励磁电流和不同气隙条件下,计算了不同磨耗量时磁轨制动器的吸力大小以及磁感应强度分布,得到了吸力最大时的磨耗量,并分析吸力最大的原因,确定了磁轨制动器最优工作状态时的磨耗量区间.

机车车辆限界标准的制定一般基于各国铁路的运营及技术装备特点,由于我国非黏着制动技术的研究及应用起步较晚,国内限界标准对相关问题的规定不明确,制约了机车车辆的升级换代和新设备的应用.近年来,非黏着制动技术的应用需求日益增长,对国内外现行的机车车辆限界标准以及非黏着制动相关的问题进行了系统对比分析,并对我国限界标准修订提出建议,为机车车辆和制动技术的发展提供依据.研究表明,国内外机车车辆限界的计算方法及下部限界规定均有差异,其中,欧洲限界标准充分考虑了近轨道区域以及与轨面接触区域的部件空间,是非黏着制动装置设计的重要依据;现有非黏着制动装置外形尺寸可满足我国限界标准的横向空间要求,但对于近轨面区域需进一步明确相关规定.

利用Flux电磁仿真软件建立某高悬挂磁轨制动器有限元模型,研究不同励磁电流大小对磁轨制动器电磁吸力特性的影响,并通过磁轨制动吸力试验台进行吸力试验,试验结果与仿真结果对比相差很小,验证了仿真结果的准确性.仿真和试验结果表明,磁轨制动器的吸力随励磁电流增加而增加,但增加速率逐渐减小.

为研究不同励磁电流下电磁铁各部分的温度分布及其随时间的变化关系,利用Flux软件建立某线性涡流制动电磁铁电磁-热-流-固耦合有限元模型,其中电磁铁与空气接触面的传热不采用添加简化、单一的对流换热系数方式,而采用固流体耦合方式模拟.通过涡流制动电磁铁试验台对电磁铁进行温升试验,分析电磁铁各零件的温升随时间的变化关系,并与仿真结果进行对比.结果表明:电磁-热-流-固耦合有限元模型可准确模拟涡流制动电磁铁各部分的温升特性;励磁电流越大,电磁线圈温升越快,达到温度限值的时间越短,越不利于电磁铁散热;传热过程中,材料的导热能力与零件之间的接触热阻对电磁铁散热影响很大;采用固流体耦合传热计算方式,可模拟电磁铁表面的温度分布,更接近实际情况.