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为了预测极靴服务寿命,确保制动可靠,通过磨损过程、制动过程、制动器/钢轨温度场的建模与仿真,计算了高速列车紧急制动过程中电磁式磁轨制动器极靴磨损量;建立了考虑速度与温度的Archard磨损模型和CRH2列车紧急制动过程的动力学模型,计算了电磁式磁轨制动器样机全程参与制动时的空气制动力、电磁制动力、制动减速度、紧急制动能量分配系数、瞬时速度和制动距离等时变参数;分析了紧急制动时电磁式磁轨制动器-钢轨-大气间的热量传递,基于Fluent软件建立了制动器/钢轨的三维温度场模型,根据制动过程时变参数获取温度场热流密度和散热加载条件;针对CRH2列车行驶速度为250km·h-1的紧急制动工况,计算了制动器极靴的磨损量。计算结果表明:在制动过程中,钢轨顶部温度随着与制动器的接触状态变化呈波动变化,在距离有效制动起点1 620m处,钢轨与8号电磁式磁轨制动器接触结束时,温度达到最大值570.76℃;CRH2列车同侧8个制动器极靴底部在制动时间为24.5s时温度达到最大值,从前到后依次为1 022.6℃、1 037.7℃、1 045.3℃、1 052.8℃、1 085.7℃、1 100.9℃、1 109.2℃、1 124.4℃,极靴磨损量从前到后依次为207.4、208.7、210.0、210.7、212.1、213.4、214.4、215.5g。可见,制动器工作会使钢轨产生热量积累,导致列车运行方向后面的电磁式磁轨制动器极靴温度较高,磨损量较大。
In order to predict service life of pole piece and ensure reliable braking, the wear amount of pole piece of electromagnetic magnetic brake was calculated through the process of wear, the braking process and the modeling and simulation of brake / rail temperature field. The dynamic models of Archard wear model and CRH2 emergency braking process considering the speed and temperature are established. The air braking force, electromagnetic braking force, braking deceleration, emergency Braking energy distribution coefficient, instantaneous speed and braking distance. The heat transfer between electromagnetic rail brake and rail-atmosphere during emergency braking is analyzed. A three-dimensional temperature field model of brake / rail is established based on Fluent software According to the time-varying parameters of braking process, the heat flux density and cooling load conditions were obtained. For the emergency braking condition with CRH2 train speed of 250km · h-1, the wear amount of the brake pole shoes was calculated. The calculation results show that during the braking process, the temperature of the top of the rail fluctuates with the change of the contact state with the brake. When the contact of the rail with the No. 8 electromagnetic rail brake ends at 1 620m from the starting point of effective braking, the temperature reaches Maximum 570.76 ℃; CRH2 train on the same side of the eight brake pole at the brake time of 24.5s at the bottom of the maximum temperature reached, followed by the order of 1 022.6 ℃, 1 037.7 ℃, 1 045.3 ℃, 1 052.8 ℃, 1 085.7 ℃, 1 100.9 ℃, 1 109.2 ℃, 1 124.4 ℃. The wear amount of the pole shoes was 207.4, 208.7, 210.0, 210.7, 212.1, 213.4, 214.4 and 215.5g from front to back. Can be seen that the brakes work will make the rail heat accumulation, resulting in the direction of the train behind the magnetic rail brake shoe temperature is high, wear a larger amount.