【作者】 崔涛；

【导师】 张卫华；

【作者基本信息】 西南交通大学 ， 载运工具运用工程， 2011， 博士

【摘要】 随着列车的高速化和轻量化发展,列车与气流的耦合振动加剧,出现了系列亟待解决的关键技术问题。具体包括：列车尾车动力学性能的恶化；侧风对列车运行安全性的威胁；高速交会压力波和气动冲击载荷对列车结构和动力学性能的影响；列车高速通过站台时的流固耦合振动导致的安全问题等。长期以来随着高速轨道交通的发展,列车空气动力学取得了丰硕的研究成果,但很少考虑列车与气流的耦合振动关系。安全问题是铁路系统问题中的重中之重,而高速列车与气流的耦合振动是一个关系到行车安全的重要工程技术问题,也是必须解决的关键工程技术问题之一。论文结合计算流体动力学理论和列车多体系统动力学理论,基于任意拉格朗日—欧拉方法,通过建立列车与气流耦合振动动力学模型,提出一种耦合分析方法,具体包括离线和在线耦合分析方法。离线耦合分析方法的流场分析中不考虑列车的振动状态,但列车系统动力响应分析中考虑气动载荷。在线耦合分析方法又可分为显式耦合分析方法和隐式耦合分析方法。其中显式耦合分析方法对列车动力响应和流场特性进行同步分析,注重相互作用过程,耗时较长；而隐式耦合方法则是选择性的对列车系统动力响应和流场特性进行关联分析,注重相互作用的最终状态,效率较高。论文通过提出的这种耦合分析方法对高速列车气流耦合振动及运行安全性展开了研究,具体的研究内容有如下几点：(1)针对无风开放空间列车与气流耦合振动问题,采用离线耦合和显式耦合分析方法对气流影响下高速列车的运行平稳性和稳定性进行分析,并与常规列车系统动力学分析结果作对比。(2)针对列车侧风安全性问题,考虑列车姿态变化,采用离线耦合、显式耦合和隐式耦合方法对特定工况下的列车运行安全性进行分析,并对不同耦合方法的分析结果作了对比。同时对多种工况下的列车运行安全性展开详细的隐式耦合分析,定义考虑姿态的列车侧风安全域。(3)采用离线耦合和显式耦合分析方法,从列车表面压力波动、气动载荷冲击、车体响应和运动稳定性出发,对不同风环境下列车高速交会安全性进行分析。比较了不同风环境和不同耦合方法下列车交会安全性的差异,并且结合线路试验结果作了对比分析。(4)针对列车高速通过站台的安全性问题,比较了初始固定姿态和侧风稳定姿态列车通过站台的碰撞危险性和运行稳定性,分析了不同工况下列车通过站台的安全性,定义了列车通过站台的安全域,并对列车高速通过时,屏蔽门的压力波动进行了研究。通过以上研究,主要结论如下：(1)通过无风开放空间内列车气流耦合振动分析,发现相对于常规分析方法,离线耦合分析方法所得的列车运行平稳性和稳定性有所降低；采用显式耦合分析方法考虑流固耦合关系后,头车、中间车和尾车前端的横向稳定性略有改善,而尾车后端的横向平稳性有所下降；考虑流固耦合关系后,由于气流对车体振动的限制,轮对振动向上传递受到了一定程度的影响,列车的运行稳定性降低。(2)通过列车侧风安全性的不同耦合方法分析,发现列车的姿态变化是其自身对侧风作用的适应性调整的结果；准确获得侧风作用下列车的稳定姿态,需要采用在线耦合分析方法；隐式耦合分析方法可以有效满足考虑姿态变化的列车侧风安全性研究；姿态变化对气动载荷的影响规律与文献中的线路试验结果具有良好的一致性；通过列车侧风安全性的隐式耦合分析,获得了不同侧风环境下列车安全运行的临界速度,定义了考虑姿态变化的列车侧风安全域；运行速度愈高,列车抵抗侧风的能力愈低,而且临界速度对侧风的敏感性增加。(3)通过对列车高速交会的流固耦合分析,发现与无风环境相比,侧风环境下表面压力波动和气动载荷冲击有增有减,背风侧列车的气动载荷冲击大于迎风侧；显式耦合分析所得表面压力波动、气动载荷冲击、车体响应和运行稳定性指标较离线耦合结果均有所增加；无论是表面压力波,还是车体动态响应,仿真结果与线路试验结果具有良好的一致性。(4)通过不同姿态列车通过站台的安全性分析,发现列车采用初始固定姿态满足分析要求。通过不同侧风风速和不同运行速度的分析,发现相同行车速度下列车距离站台的最近点横坐标与侧风风速近似成正比。列车通过站台的安全域为碰撞安全域和运行稳定性安全域的交集。列车高速通过时,屏蔽上出现类似列车交会时的压力波动。头车进出屏蔽门行车区时,屏蔽门最大气压和最小气压分别出现峰值。(5)根据相应的研究问题选择适当的分析方法,既要保证分析结果的准确性,又要提高分析效率。如选用隐式耦合分析方法来考虑侧风下列车的姿态变化；而屏蔽门表面气压分析则不需考虑列车的振动。总之,论文通过建立的列车气流耦合振动分析方法,探明了高速列车流固耦合振动导致的一系列关键问题的作用机理。通过显式耦合分析发现了气流对列车运行平稳性和稳定性的影响规律；通过列车侧风在线耦合分析发现了列车姿态变化对气动载荷和运行稳定性均产生了不可忽视的影响；考虑流固关系后列车高速交会安全性问题变得更加突出；列车高速通过站台安全性研究既要考虑流固耦合振动对运行稳定性的影响,又要防止列车与站台的碰撞。为确保行车安全,考虑流固耦合振动关系进行列车运行安全性分析是十分必要的。耦合分析方法得到了试验数据的有效验证,为流固作用下列车动力学特性研究以及列车空气动力学和列车系统动力学的交叉研究提供了思路和方法。更多还原

【Abstract】 A series of key technical issues that should be urgently solved has arisen as the coupling vibration between the train and airflow intensifies along with the high-speed and light-weight development of train. The issues include dynamic performance deterioration of the tailing vehicle, threat to running safety of train from side wind, effect on train’s structure and dynamic performance of the pressure wave and aerodynamic load impulse when two trains pass by each other at high speed, safty issues caused by fluid-solid vibration when a train passes through the platform at high speed, and so on. Although considerable achievements have been obtained in the field of train aerodynmics with development of high-speed rail transport, the coupling vibration relationship has been taken into account rarely. Safety is the all-important one among issues regarding train system. The train-airfow coupling vibration is an important engineering and technical issue concerning safety, also one of the key technical issues needed to be solved for railway development.In this paper, an analysis method for train-airflow coupling vibration including off-line and on-line coupling analysis method was proposed by establishing a train-ailfow coupling model on the basis of Arbitrary Lagrangian-Eulerian (ALE) through integrating the theory of computation fluid mechanics and train system dynamics. With regard to off-line coupling analysis method, the train’s vibration state is not taken into consideration in flow field anlysis, but the aerodynamic load is taken into account in the anlysis on dynamic response of train system. The on-line coupling analysis method includes explicit and implicit ones. The train’s dynamic response and flow field characteristic are analyzed synchronously for the explicit coupling analysis method, which focuses on the process of interaction between fluid and solid and needs more time. Whereas, for the implicit method, it focuses on the final condition of interaction between fluid and solid and needs less time as the train’s dynamic response and flow field characteristic are analyzed with selective link. The research on fluid-solid coupling vibration and running safety of high-speed train was conducted by adopting the foregoing coupling vibration analysis method in the paper, of which details are as follows:(1)For coupling vibration between airflow and train in the calm open space, the study analyzes running stationarity and stability of a high-speed train under the influence of airflow with the off-line and explicit coupling analysis method and compares relevant results with those based on conventional method. (2)As for safety problem of a train running in side wind, considering the attitude change, the study analyzes running safety of the train in specific condition with the off-line, explicit and implicit coupling analysis methods and compares relevant results acquired from these different analysis methods. At the same time, running safety of a train in different conditions is analyzed with implicit coupling analysis method and safety domain of a train in side wind is defined.(3)Adopting the off-method and explicit method, from the perspective of surface pressure wave, aerodynamic load impulse, carbody response and running stability, the study analyzes safey of two trains passing by each other in different wind environments. The differences of safety of a train in different wind environmets and acquired from different coupling methods are compared. Additionally, a comparative analysis is made with running test data.(4)With respect to the safety issue, the study compares collision risk and running stability of a train with the intial fixed attitude and the stable attitude in side wind when the train passes through the railway platform at high speed, analyzes safety of a train passing through the platform in different conditions, defines safety domain of a train passing through the platform and researches the peressure wave of shield door when a train passing through the platform at high-speed.Main conclusions as following are reached according to above discussions.(l)The train-airflow coupling analysis for a train running in the calm open space shows that train’s running stationarity and stability acquired from off-line coupling method diminish somewhat compared to those acquired from conventional computing method. After the fluid-solid coupling relationship is taken into consideration with explicit coupling analysis method, the lateral stability of leading vehicle, middle vehicle and the front end of the tailing vehicle improve slightly, but the lateral stability of the back end of tailing vehicle decreases. In addition, the upward transfer of wheel-rail vibration is influenced to some extent due to the limition of airflow to carbody’s motion, thus the train’s running stability descreaes.(2)Different coupling anlysis methods for safety of a train running in side wind show that the adaptive process to side wind’s action results in attitude change of a train. Accurate result of attitude change needs the on-line coupling analysis method. The implicit coupling method can meet the demands of study on safety of a train running side wind with considering the attitude changes. Influence of attitude changes on aerodynamic is well consistent with running test data in relevant literatures. Critical speeds of a train running safely in different side winds are found and the safety domain of train in side wind is defined with consideration of attitude changes in the implicit coupling analyses. The faster a train runs, the lower capability to withstand side wind it has, and the more sensitive to side wind the critical speed is.(3)The fluid-solid analyses on two trains passing by each other at high-speed show that, some surface pressure waves and aerodynamic load impulses rise, and others descrease in the environment with side wind compared to a calm envirement without wind. The aerodynamic load impulses of the leeward train are bigger than that of windward train. The surface pressure waves, aerodynamic load impulses, carbody responses and running stabilities obtained in the explicit coupling analysis are bigger than those in the off-line coupling analysis. Moreover, simulation results of surface pressure waves and carbody responses are well consistent with concerned running test data.(4)The safety analyses on a train with different attitudes passing through platform show that, the train with initial fixed attitude can meet the analysis demand. The analysis on different side wind speeds and running speeds indicate the abscissa of the closest point is proportional to the wind speed when a train passing through the platform at the same speed. The safety domain of a train passing through platform in side wind is the union of collision safety domain and operating stability safety domain. There is a pressure wave on the shield door when a train passes through at high-speed, which is similar to the pressure wave when two train pass by each other. The maximum and minimum values will appear respectively when the leading vehicle runs into and out of the shield door.(5) Proper methods should be taken to analyze different problems in order to ensure accuracy of analysis result and enhance analysis efficiency. For example, the implicit coupling analysis method was adopted to research the attitude changes of a train running in side wind. And the analysis on pressure wave of shield door doesn’t need to consider train’s vibration.In conclusion, the paper discusses mechanisms of a series of key issue caused by coupling vibration between high-speed train and airflow. The influence pattern of airflow on train’s running stationarity and stability is found by explicit coupling analysis. The on-line coupling analysis on a train in side wind reveals that attitude changes pose an effect that can not be ignored on aerodynamic load and running stability. The safety issue of trains passing by each other becomes more prominent after fluid-solid coupling relationship being taken into consideration. The attention should be paid to the influence of fluid-solid coupling on train’s running stability and the collsion risk between train and platform. In order to ensure train’s running safety, it is very necessary to consider the fluid-solid coupling vibration relationship for train’s running safety analysis. As the coupling analysis method is verified by test datum, it throws a light on train’s dynamic behaviour study under fluid-solid coupling relationship and offers a thought for cross-sectional studies on train’s aerodynamics and system dynamics.更多还原