Aerodynamic Features of High-Speed Maglev Trains with Different Marshaling Lengths Running on a Viaduct under Crosswinds

The safety and stability of high-speed maglev trains traveling on viaducts in crosswinds critically depend on their aerodynamic characteristics.Therefore,this paper uses an improved delayed detached eddy simulation(IDDES)method to investigate the aerodynamic features of high-speed maglev trains with different marshaling lengths under crosswinds.The effects of marshaling lengths(varying from 3-car to 8-car groups)on the train’s aerodynamic performance,surface pressure,and the flow field surrounding the train were investigated using the three-dimensional unsteady compressible Navier-Stokes(N-S)equations.The results showed that the marshaling lengths had minimal influence on the aerodynamic performance of the head and middle cars.Conversely,the marshaling lengths are negatively correlated with the time-average side force coefficient(CS)and time-average lift force coefficient(Cl)of the tail car.Compared to the tail car of the 3-car groups,the CS and Cl fell by 27.77%and 18.29%,respectively,for the tail car of the 8-car groups.It is essential to pay more attention to the operational safety of the head car,as it exhibits the highest time average CS.Additionally,the mean pressure difference between the two sides of the tail car body increased with the marshaling lengths,and the side force direction on the tail car was opposite to that of the head and middle cars.Furthermore,the turbulent kinetic energy of the wake structure on the windward side quickly decreased as marshaling lengths increased.

Current status and reflection on the development of high-speed maglev transportation

Purpose–High-speed maglev technology can address the issues of adhesion,friction,vibration and highspeed current collection in traditional wheel-rail systems,making it an important direction for the future development of high-speed rail technology.Design/methodology/approach–This paper elaborates on the demand and significance of developing high-speed maglev technology worldwide and examines the current status and technological maturity of several major high-speed maglev systems globally.Findings–This paper summarizes the challenges in the development of high-speed maglev railways in China.Based on this analysis,it puts forward considerations for future research on high-speed maglev railways.Originality/value–This paper describes the development status and technical maturity of several major high-speed maglev systems in the world for the first time,summarizes the existing problems in the development of China’s high-speed maglev railway and on this basis,puts forward the thinking of the next research of China’s high-speed maglev railway.

A study on aerodynamic noise characteristics of a high-speed maglev train with a speed of 600 km/h

Purpose–This study aims to explore the formation mechanism of aerodynamic noise of a high-speed maglev train and understand the characteristics of dipole and quadrupole sound sources of the maglev train at different speed levels.Design/methodology/approach–Based on large eddy simulation(LES)method and Kirchhoff–Ffowcs Williams and Hawkings(K-FWH)equations,the characteristics of dipole and quadrupole sound sources of maglev trains at different speed levels were simulated and analyzed by constructing reasonable penetrable integral surface.Findings–The spatial disturbance resulting from the separation of the boundary layer in the streamlined area of the tail car is the source of aerodynamic sound of the maglev train.The dipole sources of the train are mainly distributed around the radio terminals of the head and tail cars of the maglev train,the bottom of the arms of the streamlined parts of the head and tail cars and the nose tip area of the streamlined part of the tail car,and the quadrupole sources are mainly distributed in the wake area.When the train runs at three speed levels of 400,500 and 600 km$h1,respectively,the radiated energy of quadrupole source is 62.4%,63.3%and 71.7%,respectively,which exceeds that of dipole sources.Originality/value–This study can help understand the aerodynamic noise characteristics generated by the high-speed maglev train and provide a reference for the optimization design of its aerodynamic shape.

Motion stability of high-speed maglev systems in consideration of aerodynamic effects: a study of a single magnetic suspension system

In this study, the intrinsic mechanism of aerodynamic effects on the motion stability of a high-speed maglev system was investigated. The concept of a critical speed for maglev vehicles considering the aerodynamic effect is proposed. The study was carried out based on a single magnetic suspension system, which is convenient for proposing relevant concepts and obtaining explicit expressions. This study shows that the motion stability of the suspension system is closely related to the vehicle speed when aerodynamic effects are considered. With increases of the vehicle speed, the stability behavior of the system changes. At a certain vehicle speed,the stability of the system reaches a critical state, followed by instability. The speed corresponding to the critical state is the critical speed. Analysis reveals that when the system reaches the critical state, it takes two forms, with two critical speeds, and thus two expressions for the critical speed are obtained. The conditions of the existence of the critical speed were determined, and the effects of the control parameters and the lift coefficient on the critical speed were analyzed by numerical analysis. The results show that the first critical speed appears when the aerodynamic force is upward,and the second critical speed appears when the aerodynamic force is downward. Moreover, both critical speeds decrease with the increase of the lift coefficient.

Electromagnetic Analysis and Optimization of High-speed Maglev Linear Synchronous Motor Based on Field-circuit Coupling

High speed maglev train has become a new non-contact transportation mode mainly studied in recent years because of its non-sticking and high speed characteristics.Firstly,the finite element model of the long stator linear synchronous motor(LSM)is established based on the structure of the test prototype.After calculation,it is compared with the experimental data and verified.On this basis,a field-circuit coupling model based on inverter circuit is established,and the influence of carrier wave ratio change on the output characteristics of LSM is calculated and analyzed.Finally,the filter circuit is introduced into the field-circuit coupling model,and the influence of the filter circuit on the output characteristics of the LSM is compared and analyzed.

中低速磁浮最小曲线半径及缓和曲线长度研究

为研究中低速磁浮最小曲线半径及缓和曲线长度,该文基于磁浮交通线路参数的计算方法、相关要素,以及线路自身的特点,推导出适用于中低速磁浮的曲线半径、缓和曲线长度计算公式,在参考相关标准的基础上,对中低速磁浮列车以20~160 km/h速度运行时的最小平、竖曲线半径及缓和曲线长度进行了理论分析,进一步给出其建议值,并建立了考虑主动反馈控制特性的车辆模型,通过动力学仿真对取值的可靠性进行了验证。研究结果表明:最小平曲线半径取值受指向外侧的最大侧向加速度控制,最小竖曲线半径取值受凹曲线上最大法向加速度控制,当列车运行速度一定时,横坡角越大,最小平曲线半径取值越小,而纵坡对最小竖曲线半径取值几乎无影响;当横坡角为2°,列车在正常条件下运行时,最小缓和曲线长度主要受最大侧向冲击控制,在困难条件下运行时,最小缓和曲线长度主要受最大法向冲击控制,当横坡角为4°、6°,列车在正常/困难条件下运行时,最小缓和曲线长度主要受最大法向冲击控制;按横坡角最大值6°考虑,列车以160 km/h在正常条件下运行时,建议最小平曲线半径及缓和曲线长度分别取970 m、120 m。该文研究成果可为中低速磁浮交通的选线设计提供理论依据和数据参考。

新型中低速磁浮车辆动力学特性分析

针对一种速度160 km/h新型中低速磁浮悬浮架,文章运用SIMPACK多体动力学软件建立了车辆的动力学模型,分析了该悬浮架在直线以及曲线工况下的动力学特性。结果表明,直线运行工况下车辆速度可以达到160 km/h,悬浮间隙、车体振动加速度等指标均符合要求,但在120 km/h时车辆各项指标有所恶化,为减小车体共振影响,对车体振动加速度进行了频率分析并给出优化建议。在曲线工况下,车辆的导向力、空簧横向位移及滑台位移等指标均在正常范围。研究结果证明新型中低速磁浮车辆的动力学性能符合要求,相关动力学结果可为新型悬浮架后续研究及工程化提供数据支持。

高速磁浮维修基地轨道梁连接螺栓松动对轨道结构振动影响的试验研究

[目的]在列车调试过程中,高速磁浮维修基地钢制轨道梁可能因其特有的构造特性而产生较大振动,进而引发螺栓松动问题。此现象可能会导致轨道梁振动特性发生变化,而车轨耦合系统参数的变动又可能诱发列车和轨道的共振,进而对轨道结构造成潜在伤害。因此,需要探究螺栓松动对轨道梁结构振动的影响。[方法]在阐述试验设计方案及原理的基础上,深入探讨了螺栓松动对轨道梁轨道结构模态和动力响应特性的影响。在结构模态方面,分别采用脉冲激励和自然激励方式,对无载状态(即轨道空闲)及有载状态(即轨道被列车占用)下的轨道模态进行测试,利用随机子空间法进行模态辨识,最后通过稳定图分析了螺栓松动对两种状态下轨道模态的影响。在动力响应特性方面,在轨道上施加悬浮激励,螺栓在列车多次悬浮过程中逐渐松动,采集轨道梁的加速度响应信号,并在时域和频域两个方面对其进行了详细分析。[结果及结论]有载状态及无载状态下,螺栓松动均引起了模态频率的下降和振型的变化。在有载状态下,螺栓松动后阻尼比有较明显的增加。在静悬过程中,轨道梁与列车发生了共振,螺栓松动不仅影响了轨道梁的振幅,还改变了轨道梁振动的对称性。

Development of new electromagnetic suspension-based high-speed Maglev vehicles in China:Historical and recent progress in the field of dynamical simulation

High-speed Maglev is a cutting-edge technology brought back into the focus of research by plans of the Chinese government for the development of a new 600 km/h Maglev train.A Chinese‐German cooperation with industrial and academic partners has been established to pursue this ambitious goal and bring together experts from multiple disciplines.This contribution presents the joint work and achievements of CRRC Qingdao Sifang,thyssenkrupp Transrapid,CDFEB,and the ITM of the University of Stuttgart,regarding research and development in the field of high‐speed Maglev systems.Furthermore,an overview is given of the historical development of the Transrapid in Germany,the associated development of dynamical simulation models,and recent developments regarding high-speed Maglev trains in China.

600 km/h高速磁浮线路参数研究

线路参数是铁路选线最基本的设计参数,不仅是列车安全、快速和舒适运行的技术保障,而且直接影响着铁路项目的工程造价及投资等重大问题。本文基于车线行驶动力学理论,以旅客乘坐舒适度要求为标准,对600 km/h高速磁浮铁路线路平纵断面参数进行研究,总结线路参数变化规律,提出600 km/h高速磁浮铁路线路设计参数建议值。研究成果可为高速磁浮铁路选线设计提供技术参考。

中低速磁浮车辆段闯红灯防护方案

针对中低速磁浮交通车辆段闯红灯防护需求,提出车辆段RM模式闯红灯防护方案,取得良好效果,保障中低速磁浮车辆段的平稳运行。方案为后续中低速磁浮交通的建设和运营积累经验。

Adaptive fault-tolerant control of high-speed maglev train suspension system with partial actuator failure: design and experiments

High-speed maglev trains will play an important role in the high-speed transportation system in the near future.However,under the conditions of strong magnetic fields and continuous operation,the actuators of the high-speed maglev train suspension system are prone to lose partial effectiveness,which makes the suspension control problem challenging.In addition,most existing fault-tolerant control(FTC)methods for suspension systems require linearization around the equilibrium points during the controller design or stability analysis.Therefore,from a practical perspective,this study presents a novel nonlinear FTC strategy with adaptive compensation for high-speed maglev train suspension systems.First,a nonlinear dynamic model of the suspension system based on join-structure is established and the actuator failures are described.Then,a nonlinear fault-tolerant suspension control law with an adaptive update law is designed to achieve stable suspension against partial actuator failure.The Lyapunov theory and extended Barbalat lemma are utilized to rigorously prove the closed-loop asymptotic stability even if there is partial actuator failure,without any approximation to the original nonlinear dynamics.Finally,hardware experimental results are included to demonstrate the effectiveness of the proposed approach.

世界首条永磁磁浮轨道交通试验线总体设计研究

永磁磁浮轨道交通系统是一种中低速、中低运量的新型轨道交通,具有完全自主知识产权。该系统采用非接触悬浮运行,具有转弯半径小、爬坡能力强、节能环保、噪音低等优点,适用于城市、景区等常规环境,也适合高寒、沿江、荒漠等困难地势环境,可以与地铁、轻轨交通互相补充。本文从线路、车辆与限界、道岔、桥梁、静调库及工艺设计和牵引供电等多角度出发,对世界首条永磁磁浮轨道交通试验线——兴国工程试验线的总体设计进行重点阐述。研究成果可为现代智能交通系统提供借鉴和参考。

北京市轨道交通S1线车站参数化设计实践研究

城市轨道交通高架线全线各站往往具有一定程度的重复性,同时车站设计工作经常面临着不同阶段方案变化大、设计周期短、前置条件苛刻等问题。为提升车站的设计效率,实现从设计到施工的高完成度,针对项目特点,采用参数化编程的方法能有效应对这些矛盾,提升设计品质。本研究归纳了北京市轨道交通S1线车站在工程设计实践中,采用Grasshopper等参数化软件在全过程设计中的应用经验,在工作流程、架构搭建、编程要点、文件输出等问题上进行回顾总结,并探讨了其中的关键技术。

Numerical Analysis of Different Nose Shapes on the Train Aerodynamic Performance at a Windbreak Transition under Crosswinds

Based on the Unsteady Reynolds-Averaged Navier-Stokes (URANS) method, this paper studied the effect of the nose shape on the aerodynamic performance when the high-speed train subjected to a windbreak transition under crosswinds. The windbreak transition generated by the irregular terrain from the flat ground to the cutting. The results showed that with the height of the front window increased from Z ? 2 to Z + 2 (the dimensionless height), the side force coefficient Cy and rolling moment co-efficient Cmx increased by 26% and 27% for the head car, respectively. The flow structures around the lower front window were smoother than that around the higher front window. The flow structures in the higher front window resulted in more considerable positive pressure on the windward side (WWS) and top of the nose region.

真空管超高速磁浮交通系统平面曲线参数运动学分析

针对真空管超高速磁浮交通系统线路设计实践,考虑真空管道构造特性和选线灵活性,基于舒适度指标,分析平曲线参数控制因素,确定了曲线半径、缓和曲线长度取值,基于刚体运动学模型,利用质心运动定理和动量矩定理,建立车辆动力学基本方程组,对超高速条件下支撑力和导向力进行估算,分析支撑力和导向力与缓和曲线线形及欠超高之间的关系。研究结果表明:横坡与侧向加速度是影响最小曲线半径取值的关键因素,对于1000 km/h设计速度来说,最小曲线半径的取值范围为9880~138900 m;缓和曲线最小长度取值应同时满足侧向冲击、垂向冲击和舒适度指标要求,在设计速度为1000 km/h时,缓和曲线最小长度推荐取1120 m;由公式计算得出的支撑力和导向力随速度变化规律与欠超高变化趋势相同,缓和曲线线形影响支撑力和导向力变化方式,但不影响曲线上支撑力和导向力的最大值。研究成果可为真空管超高速磁浮交通系统线路设计提供参考。

中低速磁浮道岔低温适用性研究

中低速磁浮交通已经进入快速发展阶段,作为重要换线设备的中低速磁浮道岔得到推广应用。但是,现有道岔的使用温度仅适合-25~75℃,不能满足海拔较高和冬季温度较低的城市需求。文章引入Boltzmann函数对材料韧脆转变温度定量分析,选出适合在-40℃低温使用的材料,列举了适合道岔低温使用的材料,为设计者提供参考。

1000km/h真空管磁浮纵断面参数取值研究

研究目的:真空管超高速磁浮是实现超高速轨道交通发展的重要方式,本文基于1000 km/h速度需求,参考高速磁浮、高速铁路系统研究成果,展开选线设计中纵断面参数分析并给出纵断面参数建议值。研究结论:(1)考虑安全因素和运行控制系统的特点,真空管超高速磁浮线路纵坡不宜大于50‰;(2)综合考虑速度、垂向加速度、纵坡、横坡、平曲线半径的影响,最小竖曲线半径一般不宜小于78000 m,困难条件下不宜小于65000 m;(3)考虑超高速运营需求,线路竖曲线间应设置缓和曲线,缓和曲线线形建议采用三次抛物线,其最小长度一般条件下不宜小于560 m,困难条件下不宜小于335 m;(4)本研究成果可以应用于超高速磁浮项目工程线路设计。

高速磁浮轨道导向不平顺检测系统的研究

高速磁浮列车是利用电磁力实现车辆与轨道无接触高速运行的一种新型交通工具,车辆的导向和制动性能受到轨道导向不平顺的影响。为了保证高速磁浮车辆运行的安全性、稳定性和舒适性,设计一种结构简化、低成本和搭载式的磁浮轨道导向不平顺检测系统。该系统基于惯性基准法原理实现检测,由加速度计、测距传感器、数据记录仪和里程检测模块组成,并未使用陀螺仪和倾角仪测量载体的姿态角变化。分析了车辆姿态变化对导向不平顺检测误差的影响,因未修正姿态导致的检测误差绝对值在直线段轨道达到0.4 mm,而在曲线段轨道超过了3 mm。为了降低缺乏姿态观测所致误差,提出一种设计线型辅助的策略用以部分替代倾角仪功能,即以列车所在位置轨道的横坡角和纵坡角分别近似替代载体的侧滚角和俯仰角低频分量,并用于补偿加速度积分中的重力和离心力分量,仿真表明该方法可将曲线段轨道的检测误差降低至0.6 mm。此外,结合磁浮轨道刚度大、变形小以及分段铺设的特点,利用分段直线拟合方法对不平顺检测结果进行平滑处理,从而进一步降低缺乏姿态观测的影响,保证系统具有足够的检测精度。通过小车检测试验,结果表明所设计系统及数据处理方法可实现±0.5 mm之内的检测误差。

高速磁浮交通车辆检修制度优化研究

高速磁浮交通车辆现行检修制度大多采用预防性计划维修模式。计划修模式下,高速磁浮交通车辆的检修能力利用率较低,这在一定程度上影响了列车运行的可靠性和线路的运力,导致配属列车数和车辆基地规模的增加,为此亟需进行检修制度的优化。简述了现行高速磁浮交通车辆检修制度,分析其存在的不足。对高速磁浮交通车辆运行特点及零部件技术特征进行了分析,明确了高速磁浮交通车辆与传统轮轨车辆间的本质区别,二者的车辆故障规律差异很显著。基于高速磁浮交通车辆的设备特征及故障特征,对其采用均衡修的适应性及可行性进行分析。高速磁浮交通车辆具备在线诊断系统,可随时收集车辆各部件的运转状态,能适应优化后更为精益的检修制度。高速磁浮交通车辆维修工作中应引入均衡修策略,根据零部件不同的故障规律及故障影响情况,建立以零部件为重点检修对象的均衡修制度。可参考成都地铁的车辆均衡修模式,将高速磁浮交通车辆双周检、三月检及定修的检修内容拆分到月检和专项修中,以此减小车辆的维修频次,压缩列车扣修时间,提高列车利用率。