马云双 周宁 宦荣华 高强 高国强
摘 要:通过近期对高速情况下弓网系统进行深入研究,首先,对不同接触网模型建模方法进行了研究,并建立了4种接触网波动特性的研究模型,辨识了不同接触网模型结构差异造成的波动特性变化,确定了该接触网系统的波动特性,包括:波速、波长及频率等;辨识了高速气流扰动的特征,并通过对不同流固耦合仿真方法的研究,建立了弓网系统流固耦合联合仿真方法。在此基础上,对列车通过隧道以及接触网风振响应进行了相应的分析;其次,在接触网不平顺方面,对受电弓底盘阻尼器和弓头悬挂系统非线性进行实验测试和建模,同时,进一步细化了基于梁单元的接触网参变量有限元模型,从而可实现弦单元、梁单元、梁-弦混合模型的任意建模和数值仿真。针对接触网的周期性特点,以精细积分方法为基础,建立了周期子结构精细积分方法;在电接触特性方面,构建了弓网系统接触区域有限元模型,研究了弓网间隙的电场分布及其随振动间隙的变化规律,建立了弓网电磁力数值分析模型,研究了牵引电流、拉出值、振动间隙对弓网间电磁作用力的影响规律,分析了正常和瞬态短路工况下的弓网电磁作用力数值范围,设计了高压大电流弓网电接触试验系统;最后,通过开展弓网间电弧放电特性和接触网波动特性试验研究,对理论研究工作提供了数据支撑。结果表明:采用多跨实际接触网模型对波动特性研究较为合理,并通过弓网系统耦合仿真确定其接触网的波速,进而确定其频率、波长特性的方法是可行的;当列车通过隧道时,由于隧道壁面的限制,使得受电弓的气动阻力和气动抬升力较明线上运行增大,接触线的动态抬升位移也相对增加,弓网受流质量相对变差;接触网在脉动风作用下产生了较大的风振位移和风振应力,有效控制风荷载引起的接触网位移和应力对列车运行安全性十分重要;导高不平顺的阈值,可为接触网的架设、维护提供参考;在弓网耦合系统仿真中,接触网承力索采用弦单元离散,接触线采用梁单元离散,既可保证仿真结果的合理性,又能尽可能的保证计算效率;弓网电磁作用力受牵引电流影响较为显著,正常工况下弓网电磁作用力较小,而短路工况下,弓网作用力迅速增大,对弓网动态特性影响较为显著;弓网间产生的电弧对碳滑板的磨损率、弓网间摩擦副的接触表面温升的影响较大,导致电流发生畸变,对电路中的电器设备造成不利影响。
关键词:弓网 不平顺 电接触 振动特性 波动
Abstract:Pantograph and catenary system are comprehensively investigated at high speed. Firstly, different models of the catenary are established to determine the wave characteristics for this catenary. Then,the co-simulation method of fluid-structure coupled analysis for pantograph-catenary system is established. The trains passing through the tunnels and the wind-induced vibration of catenary are analyzed. Secondly, by experimental testing on the pantograph bottom damper and the pantograph head suspension system, the nonlinear characteristic curves and the corresponding mathematical models are obtained in the catenary irregularity research. Meanwhile, for numerical simulation of pantograph-catenary coupled system, the accuracy and efficiency are both satisfied if the string element is used for catenary messenger wire and the beam element is used for contact wire. In electrical content aspect, electrical field distribution and its relationship to vibration gap have been studied. Relationship among traction current, vibration gap, stagger and electromagnetic force has been studied. Finally, pantograph-catenary arc and catenary wave characteristics experiment has been conducted for supporting the theoretical research. It is demonstrated that investigating the wave characteristics of the catenary by using the actual catenary model with multiple spans is reasonable, and it is effective to determine the wave characteristics through the simulation of pantograph and catenary coupled system. Due to the effect of tunnel wall confinement, the aerodynamic drag, lift forces of pantograph and uplift displacements of the contact wire are increased. It is important to effectively control the displacements and stresses of catenary induced by the wind loads. On the other hand, catenary irregularity threshold provides reference for catenary installation and maintenance. For simulation of pantograph-catenary coupled system, the accuracy and efficiency are both satisfied if the string element is used for catenary messenger wire and the beam element is used for contact wire. Electromagnetic force is small in normal situation. But it will enlarge rapidly in short circuit and affects dynamic features of pantograph-catenary obviously. Pantograph- catenary arc has large influence on wear rate of carbon slipper and contact surface temperature rise, lead to current distortion of circuit for affecting the electrical equipment adversely.
Key Words:Pantograph-catenary;Irregularity;Electrical contact;Dynamic characteristic;Wave propagation
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