In this study, numerical optimisation and experimental validation of a divided rail freight brake disc crown made of grey cast iron EN-GJL-250 is presented.The analysed brake disc is used in rail freight wagons and po...In this study, numerical optimisation and experimental validation of a divided rail freight brake disc crown made of grey cast iron EN-GJL-250 is presented.The analysed brake disc is used in rail freight wagons and possesses a load capacity of 22.5 tons per axle. Two of the divided rail freight brake discs are mounted on each axle.With the aid of numerical analysis, the thermal dissipation properties of the brake disc were optimised and ventilation losses were reduced, and the numerical results were compared with experimental results. A one-way fluid–structure interaction analysis was performed. A computational fluid dynamic model of a divided rail freight brake disc, used to predict air flow properties and heat convection, was incorporated into a finite element model of the disc and used to evaluate the temperature of the disc. A numerical parametrical optimisation of cooling ribs of the brake disc was also performed, and novel optimised cooling ribs were developed. A transient thermal numerical analysis of the brake disc was validated using temperature measurements obtained during a braking test on a test bench. The ventilation losses of the brake disc were measured on a test bench specifically designed for the task, and the losses were compared to the simulation results. The experimentally obtained ventilation losses and temperature measurements compared favourably with the simulation results, confirming that this type of simulation process may be confidently applied in the future. Through systematic optimisation of the divided rail freight brake disc, ventilation losses were reduced by 37% and the mass was reduced by 21%, resulting in better thermal performance that will bring with it substantial energy savings.展开更多
Large goods transported in railway are kinds of special goods and they are very important in national construction. In order to transport safely, loading and reinforcing schemes must be made first. How to design a rea...Large goods transported in railway are kinds of special goods and they are very important in national construction. In order to transport safely, loading and reinforcing schemes must be made first. How to design a reasonable scheme will be affected by many factors. This paper presents the characteristic of the large goods, summarizes the process of designing a loading and reinforcing scheme of large good, then probes the factors of affecting the loading and reinforcing scheme and gives a detail analysis. It’s considered that those out-of-gauge and overweight degree of goods, center-of- gravity height of a loaded wagon, position of center-of-gravity of goods, type of wagon for using, reinforcement material and reinforcement method, transport expense and transport organization could affect a scheme in the aspects of safety, economy, rapidity and convenience. This conclusion will instruct and help to make a good scheme.展开更多
为提升复杂电磁环境下货运高铁车厢内部电磁敏感设备的安全性,以高空核爆电磁脉冲(high-altitude electromagnetic pulse,HEMP)为激励源,使用场路耦合的方法对货运高铁车厢内含有直流-直流(direct current to direct current,DC/DC)转...为提升复杂电磁环境下货运高铁车厢内部电磁敏感设备的安全性,以高空核爆电磁脉冲(high-altitude electromagnetic pulse,HEMP)为激励源,使用场路耦合的方法对货运高铁车厢内含有直流-直流(direct current to direct current,DC/DC)转换器的电源机箱内部PCB的电场强度及感应电流进行分析。首先,在电磁仿真软件中建立货运高铁电场环境仿真模型;其次,将机箱放置于车厢内部不同位置,使用HEMP从上部和侧面2个方向对车厢进行辐照,采用有限积分法(FIT)预测HEMP辐照下车厢内部的电场分布并计算机箱内部感应电场强度;然后,使用法兰同轴装置法分析在30~300 MHz内机箱铝合金材质的屏蔽效能;最后,利用场路耦合的方法得到机箱内部PCB电路板的电场强度以及感应电流。结果表明:电场峰值为50 kV/m的HEMP,在距离核爆点水平距离30 km处侧面辐照车厢时,车厢中间靠近车窗位置的电场强度较大;3A21铝含量机箱可有效抑制电场干扰;机箱内部PCB电路板上感应电流峰值为1.9 mA,符合GB 17625.1—2022标准要求;机箱内部PCB电路板上电场强度峰值为270 V/m时,PCB电路工作正常,没有偏离规定的指标值,符合GJB 151B—2013标准中RS103电场辐射敏感度要求。研究结果可为HEMP辐照条件下高铁货物运输电的磁防护提供依据。展开更多
基金supported by the European Union’s Horizon 2020 researchinnovation programme FUTURA under Grant Agreement No. 700985
文摘In this study, numerical optimisation and experimental validation of a divided rail freight brake disc crown made of grey cast iron EN-GJL-250 is presented.The analysed brake disc is used in rail freight wagons and possesses a load capacity of 22.5 tons per axle. Two of the divided rail freight brake discs are mounted on each axle.With the aid of numerical analysis, the thermal dissipation properties of the brake disc were optimised and ventilation losses were reduced, and the numerical results were compared with experimental results. A one-way fluid–structure interaction analysis was performed. A computational fluid dynamic model of a divided rail freight brake disc, used to predict air flow properties and heat convection, was incorporated into a finite element model of the disc and used to evaluate the temperature of the disc. A numerical parametrical optimisation of cooling ribs of the brake disc was also performed, and novel optimised cooling ribs were developed. A transient thermal numerical analysis of the brake disc was validated using temperature measurements obtained during a braking test on a test bench. The ventilation losses of the brake disc were measured on a test bench specifically designed for the task, and the losses were compared to the simulation results. The experimentally obtained ventilation losses and temperature measurements compared favourably with the simulation results, confirming that this type of simulation process may be confidently applied in the future. Through systematic optimisation of the divided rail freight brake disc, ventilation losses were reduced by 37% and the mass was reduced by 21%, resulting in better thermal performance that will bring with it substantial energy savings.
文摘Large goods transported in railway are kinds of special goods and they are very important in national construction. In order to transport safely, loading and reinforcing schemes must be made first. How to design a reasonable scheme will be affected by many factors. This paper presents the characteristic of the large goods, summarizes the process of designing a loading and reinforcing scheme of large good, then probes the factors of affecting the loading and reinforcing scheme and gives a detail analysis. It’s considered that those out-of-gauge and overweight degree of goods, center-of- gravity height of a loaded wagon, position of center-of-gravity of goods, type of wagon for using, reinforcement material and reinforcement method, transport expense and transport organization could affect a scheme in the aspects of safety, economy, rapidity and convenience. This conclusion will instruct and help to make a good scheme.
文摘为提升复杂电磁环境下货运高铁车厢内部电磁敏感设备的安全性,以高空核爆电磁脉冲(high-altitude electromagnetic pulse,HEMP)为激励源,使用场路耦合的方法对货运高铁车厢内含有直流-直流(direct current to direct current,DC/DC)转换器的电源机箱内部PCB的电场强度及感应电流进行分析。首先,在电磁仿真软件中建立货运高铁电场环境仿真模型;其次,将机箱放置于车厢内部不同位置,使用HEMP从上部和侧面2个方向对车厢进行辐照,采用有限积分法(FIT)预测HEMP辐照下车厢内部的电场分布并计算机箱内部感应电场强度;然后,使用法兰同轴装置法分析在30~300 MHz内机箱铝合金材质的屏蔽效能;最后,利用场路耦合的方法得到机箱内部PCB电路板的电场强度以及感应电流。结果表明:电场峰值为50 kV/m的HEMP,在距离核爆点水平距离30 km处侧面辐照车厢时,车厢中间靠近车窗位置的电场强度较大;3A21铝含量机箱可有效抑制电场干扰;机箱内部PCB电路板上感应电流峰值为1.9 mA,符合GB 17625.1—2022标准要求;机箱内部PCB电路板上电场强度峰值为270 V/m时,PCB电路工作正常,没有偏离规定的指标值,符合GJB 151B—2013标准中RS103电场辐射敏感度要求。研究结果可为HEMP辐照条件下高铁货物运输电的磁防护提供依据。
