环境风对高速铁路接触线波动速度的影响

基于空气动力学理论分别推导了作用在接触线上的空气阻尼和脉动风气动载荷, 并将空气动力项添加至接触线波动速度公式中进行修正; 通过风洞试验和CFD绕流仿真得到了横风环境下的气动阻力系数, 分析了不同空气阻尼下接触线波动速度的变化规律; 基于AR模型和接触网的结构特性, 建立了具有时间和空间相关性的接触网脉动风场, 通过仿真计算分析了脉动风速和风攻角对接触线波动速度的影响。研究结果表明: 静风载荷引起的接触线空气阻尼很小, 当平均风速达到30 m·s-1时, 接触线空气阻尼仅为0.3, 接触线波动速度为549.1 km·h-1左右, 因此, 空气阻尼不会对接触线波动速度产生较大影响; 当来流风攻角为60°, 平均风速不大于10 m·s-1时, 脉动风下接触线波动速度标准差和最值差分别小于1和6 km·h-1, 此时接触线波动速度相对无风情况变化较小, 脉动风载荷对接触线波动速度的影响不明显; 当风速达到40 m·s-1时, 接触线平均波动速度较无风情况下降39.39 km·h-1, 且其标准差和最值差分别达到11.84和75.98 km·h-1, 此时接触线波动速度出现大幅下降与振荡, 最小波动速度低至474.16 km·h-1, 因此, 脉动风下风速越大, 接触线波动速度受脉动风载荷影响越显著; 当风速保持30 m·s-1, 来流风攻角为0°~30°时, 接触线波动速度标准差和最值差分别小于1和5 km·h-1, 此时脉动风载荷对接触线波动速度的影响较小; 当风攻角为90°时, 接触线波动速度标准差和最值差分别达到12.38和73.19 km·h-1, 此时接触线波动速度出现大幅下降与振荡, 最小波动速度低至472.91 km·h-1, 因此, 脉动风下来流风越偏于水平方向, 对接触线波动速度的影响越小。 

Influence of environmental wind on fluctuation velocity of contact wire of high-speed railway

The air damping and pulsating wind aerodynamic load acting on the contact wire were respectively deduced based on the aerodynamic theory, and the aerodynamic term was added to correct the formula of fluctuation velocity of contact wire. Through the wind tunnel test and computational fluid dynamics(CFD), the aerodynamic drag coefficient under the transverse wind environment was obtained, and the variation rules of fluctuation velocity of contact wire under different air dampings were analyzed. Based on the AR model and the structural characteristics of catenary, the pulsating wind field of catenary with time and space correlation was established. The influences of pulsating wind speed and wind attack angle on the fluctuation velocity of contact wire were analyzed through the simulation. Research result shows that the air damping of contact wire caused by the static wind load is very small. When the average wind speed reaches 30 m·s-1, the air damping acting on the contact wire is only 0.3, and the fluctuation velocity of contact wire is stable at about 549.1 km·h-1. Therefore, the air damping will not have a great impact on the fluctuation velocity of contact wire. When the wind attack angle of incoming wind is 60°, and the average wind speed is no more than 10 m·s-1, the standard deviation and difference between the maximum and the minimum fluctuation velocities of contact wire under the pulsating wind are less than 1 and 6 km·h-1, respectively. In this case, the fluctuation velocity of contact wire has little change compared with the non-wind condition, and the influence of pulsating wind load on the fluctuation velocity of contact wire is not obvious. When the wind speed reaches 40 m·s-1, the average fluctuation velocity of contact wire decreases by 39.39 km·h-1 compared with the non-wind condition, and the standard deviation and difference between the maximum and the minimum fluctuation velocities reach 11.84 and 75.98 km·h-1, respectively. At this point, the fluctuation velocity of contact wire decreases and oscillates sharply, and the minimum is as low as 474.16 km·h-1. Therefore, the larger the wind speed is under the pulsating wind, the more significant the impact of pulsating wind load is on the fluctuation velocity of contact wire. When the wind speed is maintained at 30 m·s-1, and the attack angle of incoming wind is 0°-30°, the standard deviation and difference between the maximum and the minimum fluctuation velocities are less than 1 and 5 km·h-1, respectively. In this case, the pulsating wind load has little influence on the fluctuation velocity of contact wire. When the wind attack angle is 90°, the standard deviation and difference between the maximum and the minimum fluctuation velocities reach 12.38 and 73.19 km·h-1, respectively. At this point, the fluctuation velocity of contact wire decreases and oscillates sharply, and the minimum is as low as 472.91 km·h-1. Therefore, under the action of pulsating wind, the more the incoming wind tends to the horizontal direction, the less influence it has on the fluctuation velocity of contact wire.