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基于青藏高速公路试验工程的实测资料,利用数值模拟系统分析了通风路基通风管内的空气流动特性和变化规律.研究表明,当外界环境风速一定时,通风管内不同区域流动特征显著不同,表现为较为明显的三段性:在入口扰动区段,管内空气紊流强度最大;中部为完全湍流区,紊流强度最弱;出口射流影响区的紊流强度介于入口扰动区和完全湍流区之间.随着外界环境风速的增加,管内空气流速相对环境风速增加的量值随之增加,总体呈现非线性快速增加的趋势;入口扰动响应的长度和紊流强度增加最显著;尾部射流影响区由于受到空气流动惯性等因素影响,其长度以非线性加速减小,其空气运动轨迹的振动幅度以非线性加速提高.管内各区域空气流动特性的不同是造成通风管不同部位局部换热量差异的根本原因,这些流动特性的存在进一步叠加,或是导致通风管路基阴阳坡效应的重要因素之一.
Based on the measured data of the Qinghai-Tibet Highway experimental project, the numerical simulation system was used to analyze the air flow characteristics and the variation regularity of the ventilated subgrade ventilation duct.The results show that when the ambient air velocity is constant, the flow characteristics in the different sections of the ventilation duct are significantly different The obvious three-stage nature: the turbulence intensity is the highest in the turbulent zone and the turbulence intensity is the weakest in the middle; the turbulence intensity in the outlet jet-affected zone is between the turbulence zone and the complete turbulence zone .With the increase of ambient wind speed, the magnitude of relative increase of ambient wind speed in air velocity in the pipe increases with the increase of non-linearity, and the length and turbulence intensity of entrance disturbance increase most obviously. The influence zone of tail jet Affected by the air inertia and other factors, the length of the air duct decreases nonlinearly, and the amplitude of the air motion trajectory increases nonlinearly. The difference of air flow in different regions of the duct is caused by the difference of local heat transfer The root cause is the further superposition of the presence of these flow properties, One of the important factors that effect.