路堤块石自然对流特性的室内试验研究  

Laboratory Experiment of Natural Convection Characteristics of Embankment Block Stones

作　　者：卞晓琳[1] 何平[1] 吴青柏[2] 施烨辉[1] 

机构地区：[1]北京交通大学隧道及地下工程教育部工程研究中心,北京100044 [2]中国科学院寒区旱区环境与工程研究所冻土工程国家重点实验室,甘肃兰州730000

出　　处：《铁道学报》2010年第5期77-81,共5页Journal of the China Railway Society

基　　金：国家自然科学基金(50778012;41002090)

摘　　要：通过室内试验,对青藏铁路路堤块石自然对流过程中风速场和温度场特性及其变化规律进行研究。结果表明:在初始控温一段时间后,风速场趋于稳定,对流涡包由无序状态逐渐发展为单胞状态;降温过程中,块石层内温度场的变化较规律,尽管对流涡包形状和大小稍有变化,但一直处于单胞状态,对流中心位于块石层中部;尽管温度场变化会引起风速场变化,但当温差达到一定值后,虽继续增大,最大风速基本不再变化,且仍位于块石层中部;自然调温过程中,由于产生热交换,块石层内温度场发生较大变化,块石层内整体温度升高,且温度场变化较混乱,风速场极不稳定,对流涡包由较为规则的单胞状态,逐渐进入无序状态。The characteristics and changing law of wind velocity fields and temperature fields in block stones of the embankments of the Qinghai-Tibet Railway in the process of natural convection are studied by laboratory experiments,and contour charts of wind velocities and temperatures are given.The results show as follows： Velocity fields tend to be stable and convection cells develop from disorder to a state of single cells gradually after a period of time of temperature controlling;in the cooling process,temperature fields change regularly,convection cells remain in the single-cell state although changing in shape and size slightly,and the convection center locates in the middle of the block stone layer;temperature field changes cause wind velocity field changes,however,when the temperature difference reaches a certain value,the maximum wind speed keeps unchanged and independent of continuous increasing of the temperature difference and stays in the middle of the block stone layer;in the natural temperature adjusting process,due to generation of heat exchanges,the overall temperature in the block stone layer rises,the temperature field changes widely,the wind speed field becomes highly unstable and convection cells develop from a regular single-cell state to disorder generally.

关 键 词：自然对流 风速场 温度场 对流涡包 

分 类 号：U213.13[交通运输工程—道路与铁道工程]