横风作用下高速列车-桥梁系统气动特性风洞试验

Wind tunnel experiment on aerodynamic characteristics of high-speed train-bridge system under crosswind

为研究高速列车在运营过程中的气动特性,分析其气动特性变化机理,设计了2种高速列车-桥梁系统的气动特性风洞试验方案;开发并建立了适用于在风洞中的高速列车-桥梁系统试验方法与系统;试验系统分为运动系统与数采系统2个部分;运动系统基于惯性驱动原理,以高速伺服电机为驱动力,通过高强度旋转传送带将缩尺比为1∶8~1∶30的移动车辆模型在风洞中以最高速度50 m·s^-1模拟真实运行环境中运行;在运动系统的搭载下,自主研发了一套数采系统,并在风洞实验室中对有无横风作用下的列车进行了气动特性测试。分析结果表明:试验方法与系统适用于加减速距离短、瞬时加速度大的试验场景,且不受车辆外形与基础设施的限制,可降低设计成本,提高试验的安全与稳定性;标准误差与平均值之比均不大于10%,表明数采系统测试的车辆气动特性有较好的平稳性和可重复性,能够精准得到列车在不同试验条件下的气动特性;通过对比有无横风作用下的列车气动特性,得到列车速度对车辆的气动特性影响极其重要;列车高速移动时,其因速度产生的气动影响远远大于横风,且表面测点平均风压系数最大值可达-10,反映了静态模型的试验方式不能够满足模拟列车高速运行时气动特性状态。

To study the aerodynamic characteristics of a high-speed train in operation and analyze the mechanism of aerodynamic characteristics change, two wind tunnel experimental schemes for aerodynamic characteristics of the high-speed train-bridge system were designed. A high-speed train-bridge test method and system appropriate for wind tunnel were developed and established. The system consisted of two parts including the motion system and the data acquisition system. The motion system was based on the inertial drive mechanism, the high-speed servo motor served as the power, through the high strength rotary conveyor belt, and the moving vehicle model with a scale ratio of 1∶8-1∶30 with a maximum speed of around 50 m·s^-1could run in the wind tunnel to simulate the real operating environment.Taking the motion system as the carrier, a set of data acquisition systems was developed for measuring the aerodynamic characteristic of trains with or without the crosswind in the wind tunnel. Analysis result shows that the experimental method and system can be applied to the test scenarios with a short acceleration-deceleration distance and the high instantaneous acceleration. The system is not only free from the shape of vehicle and infrastructure but also reduces the design cost and improves the safety and stability of test.The standard error-mean value ratios are less than 10%, which shows that the aerodynamic characteristics of the train tested by the data acquisition system have good stability and repeatability, the aerodynamic characteristics of train in different tests can be obtained accurately. By comparing the test of train with or without the crosswind,the impact of speed of moving train on the aerodynamic is extremely important.While the train running at high speed, the aerodynamic effects due to the speed of train are much larger than the crosswind,and the mean wind pressure coefficient is up to-10, which reflects that the static model test method can not meet the requirements of the simulation of the aerodynamic characteristics of the train in high-speed operation. 1 tab, 8 figs, 26 refs.