【作者】 张涛；

【导师】 李宗义；

【作者基本信息】 兰州交通大学 ， 车辆工程， 2022， 硕士

【摘要】 我国西部地区地貌复杂多变,铁路沿线存在多种形式的路堑,而路堑深度、路堑边坡坡率的不同使得运行列车的气动力发生急剧变化,且该地区常年遭遇季节性的大风、沙尘活动频繁,这对列车的安全平稳运行造成十分不利的影响。此外,我国兰新铁路上运行着许多的铁路车辆,其中客车、敞车、罐车、和棚车这4种车型应运最为广泛。横风作用下,棚车的侧滚力矩最大、稳定性最弱。因此,研究风沙环境下不同路堑类型对棚车气动性能的影响及危险地段的防风沙措施,对保证列车的安全平稳运行至关重要。本文采用数值计算的方法,对棚车运行速度为120 km/h,横风风速分别为10 m/s、20 m/s、30 m/s、40 m/s和50 m/s,路堑深度分别为平直地面(0m路堑)、3m路堑、5m路堑和8m路堑,路堑边坡坡率分别1:1、1:1.25、1:1.5,线路位置分别为一线和二线等不同工况下的气动力性能进行数值仿真分析,进而提出危险地段的防风沙措施,主要研究内容如下:(1)研究风沙环境下路堑深度、路堑边坡坡率及线路位置对棚车气动性能的影响。首先,分析净风工况下,路堑深度及路堑边坡坡率对棚车气动性能的影响;其次,分析风沙工况下路堑深度、路堑边坡坡率及线路位置对棚车气动性能的影响。(2)研究结果表明:风沙环境下,随着路堑深度的增加,棚车的气动性能得到改善;风沙环境下,随着路堑边坡坡率的增加,棚车的气动力逐渐增加;风沙环境下,线路位置对棚车气动力的影响不是很明显。同净风环境相比,风沙环境下棚车的气动力更大,但同沙粒的作用效果相比,横风风速的变化才是引起棚车气动力变化的主要原因。(3)根据研究结果,对典型地段安装挡风墙进行优化。风沙环境下,列车在深度为3m、边坡坡率为1:1.5的路堑上运行时,第一节棚车的气动力比较复杂,强风沙环境下容易发生倾覆。所以,在路堑迎风侧设置挡风墙对车辆气动力进行优化。设置挡风墙后,第一节棚车的气动力发生了显著变化,其阻力减少了8.4%、侧向力减少了31.8%、升力减少了35.6%、倾覆力矩减少了33.8%。更多还原

【Abstract】 The landforms in the western region of my country are complex and changeable.There are various forms of cuttings along the railway lines.The different depths and slopes of the cuttings make the aerodynamic forces of the running trains change sharply,and the region encounters seasonal strong winds and frequent sand and dust activities all year round.It has a very negative impact on the safe and smooth running of the train.In addition,there are many railway vehicles running on the Lanzhou-Xinjiang Railway in my country,among which the four types of passenger cars,gondolas,tank cars,and boxcars are the most widely used.Under the action of cross wind,the rolling moment of the boxcar is the largest and the stability is the weakest.Therefore,it is very important to study the influence of different cutting types on the aerodynamic performance of the boxcar and the sand prevention measures in the dangerous area under the sandstorm environment to ensure the safe and stable operation of the train.In this paper,the numerical calculation method is adopted.The running speed of the boxcar is 120 km/h,the cross wind speed is 10 m/s,20 m/s,30 m/s,40 m/s and 50 m/s,and the cutting depth is respectively numerical simulation analysis was carried out for the aerodynamic performance under different working conditions such as straight ground(0m cutting),3m cutting,5m cutting and 8m cutting,and the cutting slope ratio was 1:1,1:1.25,1:1.5,etc.The main research contents are as follows:(1)The effects of cutting depth,cutting slope rate and line position on the aerodynamic performance of boxcars in wind-sand environment were studied.Firstly,the influence of the cutting depth and the cutting slope rate on the aerodynamic performance of the boxcar is analyzed under the clean wind condition;Secondly,the influence of cutting depth,cutting slope rate and line position on the aerodynamic performance of the boxcar under the sandstorm condition is analyzed.(2)The results show that the aerodynamic performance of the boxcar is improved with the increase of the cutting depth under the sandstorm environment;the aerodynamic force of the boxcar increases gradually with the increase of the slope rate of the cutting side under the sandstorm environment;the influence of the line position on the aerodynamic force of the boxcar is not obvious under the sandstorm environment.Compared with the clean wind environment,the aerodynamic force of the boxcar is greater in the sandstorm environment,but compared with the effect of sand particles,the change of the cross-wind wind speed is the main reason for the aerodynamic change of the boxcar.(3)According to the research results,optimize the setting of windshields in dangerous areas.In the sandstorm environment,when the train runs on a cutting with a depth of 3m and a slope ratio of 1:1.5,the aerodynamic force of the first boxcar is relatively complicated,and it is prone to overturning in the sandstorm environment.Therefore,setting a windshield on the windward side of the cutting can optimize the vehicle aerodynamic force.After installing the windshield,the aerodynamic force of the first boxcar has changed significantly,its resistance is reduced by 8.4%,the lateral force is reduced by 31.8%,the lift force is reduced by 35.6%,and the overturning moment is reduced by 33.8%,which is a great improvement.更多还原