透壁通风管增强开放碎石路堤降温效果试验

通过4种不同实验条件下透壁通风管开放碎石路堤试样室内试验研究了通风情况对透壁通风管增强开放碎石路堤降温效应的影响。比较4种实验结果发现,透壁通风管开放碎石路堤存在碎石表面单纯热传导传热、外界空气通过碎石路堤开放表面与碎石层内孔隙空气直接循环产生的强迫对流传热、通风管管壁与管内空气的对流换热以及管内空气通过管壁透气小孔与附近碎石层内孔隙空气直接循环产生的强迫对流传热4种传热过程。对于仅负温通风的透壁通风管开放碎石路堤,通过开放表面及管壁透气小孔使外界冷空气与碎石层内孔隙空气形成循环,从而显著增强了路堤冬季冷空气引起的降温效应。

Experimental investigation on cooling capability of open crushed rock embankment enhanced by perforated ventilation pipe

Laboratory experiments on the cooling capability of crushed rock embankment samples with a perforated ventilation pipe and an air permeable top surface are performed.The impact of mechanism on the cooling capability of the open crushed rock embankment enhanced by a perforated ventilation pipe is analyzed.The analysis indicates that the heat transfer processes in the crushed rock embankment with a perforated ventilation pipe and an air permeable surface include pure heat conduction,forced convection due to the pore air motion in the crushed rock layer forming directly a complete circulation in conjunction with the ambient air by the small holes of the perforated ventilation pipe wall,convective heat transport between the ambient air and the surface of pipe wall,and forced convection that occurs in the crushed rock layer around the perforated pipe forming directly a pore air circulation in conjunction with the ambient air by the small holes of perforated pipe wall.Under the air permeable top surface and only ventilating during the negative temperature period,a crushed rock embankment embedded a perforated ventilation pipe may enhance the cooling capability of the embankment base due to winter-time air motions in the crushed rock layer forming a complete pore air circulation in conjunction with the ambient cold air via the small holes of perforated pipe wall and the air permeable top surface.