基于流固耦合的大风区接触网正馈线舞动机制分析

为进一步明确挡风墙尾流影响下接触网正馈线的舞动机制,以兰新高铁接触网正馈线为研究对象,基于空气动力学理论,建立了接触网正馈线风致振动响应的分析模型。采用流固耦合方法对不同固有频率比和自由度的二维接触网正馈线模型进行了时程分析。研究结果表明:频率比和自由度对接触网正馈线的舞动幅值存在较大的影响。频率比越小,接触网正馈线的振幅受风速影响越大,接触网正馈线发生舞动时的风速范围更广。垂直单自由度系统中接触网正馈线的舞动幅值大于垂直-水平两自由度系统中接触网正馈线的舞动幅值,表明接触网正馈线的水平振动对垂直振动存在一定限制作用。当接触网正馈线在挡风墙尾流影响下发生振动时,正馈线的风攻角不断发生变化。迎风角较大时,正馈线垂直方向气动力幅值增大,更易引起正馈线垂直方向的大幅舞动,并将接触网正馈线的舞动模式归属为无覆冰条件下的Den Hartog舞动。研究结果进一步明确了大风区段无覆冰条件下接触网正馈线的舞动机制,为接触网正馈线舞动的防治提供一定的理论支撑。

Analysis of catenary positive feeder galloping mechanism in strong wind section based on fluid-structure interaction

To better understand the mechanism of impact of windbreak wall wake on the galloping of catenary positive feeder, this study establishes an analysis model for wind-induced vibration response of positive feeder in light of the aerodynamic theory, focusing on the positive feeder of LanzhouUrumqi high speed railway. The fluid-structure interaction method is used to analyze the time history of two-dimensional models with different natural freguency rations and degrees of freedom. The results show that both the degree of freedom and the frequency ratio significantly impact the galloping amplitude of the positive feeder. A lower frequency ratio amplifies the impact of wind speed on the amplitude of the positive feeder and extends the range of wind speeds triggering the galloping of the positive feeder. The galloping amplitude of the positive feeder in the vertical single-degree-of-freedom system is greater than that in the vertical-horizontal two-degree-of-freedom system, indicating that the horizontal vibration of the positive feeder has a certain limiting effect on the vertical vibration. When the positive feeder vibrates in the wake of windbreak wall, the windward angle of the positive feeder is constantly changing. A larger windward angle is more likely to induce substantial galloping of the positive feeder. The galloping mode of the positive feeder of the catenary in the strong wind section is determined as Den Hartog galloping without icing. The research results offer a deeper understanding of the galloping mechanism of the positive feeder under the condition without icing in the strong wind section, providing theoretical insights into mitigating and controlling the galloping of the positive feeder of the catenary.