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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。
The effects of ventilation on the cooling effect of the open ventilated duct in enhancing the open crushed stone embankment were tested in four different experimental conditions. Comparing the results of four kinds of experiments, it is found that the open crushed stone embankment of transmural ventilation pipe has the mere heat conduction and heat transfer on the gravel surface, the forced convection heat generated by the direct circulation of outside air through the open surface of the gravel embankment and the pore air in the gravel layer, Convection heat transfer between tube wall and tube air, and forced convection heat transfer generated by the direct circulation of air in the tube through the air-permeable holes in the tube wall and the pore air in the vicinity of the crushed stone layer. For the open crushed stone embankment of translucent ventilated duct with only negative temperature ventilation, the external cold air and the pore air in the gravel layer form a circulation through the open surface and the ventilation holes on the pipe wall, thereby significantly reducing the cooling effect caused by cold air in winter in the embankment .