摘要
沙漠地区的铁路时常面临风沙危害,常对列车的运行安全及维修造成严重影响,因此铁路沿线布置了多种风沙防护设施.缓和式路堤可能会减小风阻,使风沙快速流过路堤,因此其风沙流特性有待验证.以缓和式路堤为研究对象,采用欧拉双流体模型,以风速廓线作为边界条件,利用流体力学软件对比分析不同结构路堤周围的风沙流场,在此基础上揭示了不同摩阻风速对路堤积沙的影响.研究结果表明:各种路堤周围的流场均形成了减速区、回流区及加速区;在两侧下凹坡路堤的顶面出现较强涡流,最小风速是普通路堤的2.3倍,同时在路堤背风坡中部和回流区尾部之间形成长达45 m的回流区;两侧下凹坡结构有利于减弱风沙运动阻力,使这种路堤积沙量最少,比普通路堤低17.5%;当摩阻风速适中时,两侧下凹坡路堤顶部形成较强回流,输沙作用明显.因此,两侧下凹坡的缓和式路堤有助于风沙快速通过轨道,是一种输沙性能良好的路堤结构.
Desert railways often face the wind-sand hazard,which often have a serious impact on the safety and maintenance of trains.Therefore,a variety of wind-sand protection facilities are arranged along the railway.The gentle embankment may reduce the wind resistance and make the sand flow through the embankment quickly,so its characteristics of wind-blown sand flow need to be verified.This paper takes the gentle embankment as the research object,adopts the Euler two-fluid model,takes the velocity profile as the boundary condition,and uses the fluid mechanics software to compare and analyze the wind-sand flow field around the embankment with different structures.On this basis,the influence of different friction velocity on embankment sand accumulation is studied.Research indicates:The flow fields around various embankments have formed deceleration zone,recirculation zone and acceleration zone.Strong eddy currents appear on the top surface of the embankment with concave slopes on both sides,and the minimum velocity is 2.3 times that of general embankment.Meanwhile,a 45 m recirculation zone is formed between the middle of the leeward slope of the embankment and the end of the return zone;the concave slope structure on both sides is helpful to weaken the resistance of wind and sand movement,so that the amount of sand accumulation on the embankment is the least,which is 17.5%lower than that of general embankment.When the frictional velocity is moderate,the top of the concave slope embankment on both sides forms a strong backflow,and the sand transport effect is obvious.Therefore,the embankment with concave slopes on both sides helps wind-blown sand to pass through the track quickly,which is an embankment structure with excellent sand transport performance.
作者
徐建刚
黄宁
石广田
张小安
XU Jian-gang;HUANG Ning;SHI Guang-tian;ZHANG Xiao-an(School of Railway Technology,Lanzhou Jiaotong University,Lanzhou 730070,China;Key Laboratory of ServiceEnvironment and Intelligent Operation&Maintenance of Rail Transit,Lanzhou Jiaotong University,Lanzhou 730070,China;Key Laboratory of Mechanics on Disaster and Environment in Western China,the Ministry of Education of China,Lanzhou 730000,China;School of Mechanical Engineering,Lanzhou Jiaotong University,Lanzhou 730070,China)
出处
《兰州交通大学学报》
CAS
2021年第3期78-85,共8页
Journal of Lanzhou Jiaotong University
基金
国家自然科学基金项目(51868037)
国家自然科学基金重大项目(11790280)
甘肃省科技计划资助(20JR5RA381)。
关键词
沙漠铁路
缓和式路堤
风沙流
输沙
数值模拟
desert railway
gentle embankment
wind-sand flow
sand transport
numerical simulation
