Convective heat transfer and evaporative heat removal in embankment with perforated ventilation pipe
Convective heat transfer and evaporative heat removal in embankment with perforated ventilation pipe
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DOI：
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发表时间：
2012
影响因子：
1.5
通讯作者：
Wang Shuang-jie
中科院分区：
文献类型：
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作者：
Wang Shuang-jie
多孔通风管管道通风系统中，空气与管壁之间的对流换热和管壁小孔内土壤表面的蒸发排热是两种传热方式，研究了多孔通风管开孔率、开孔率、土壤表面温度和土壤表面温度对多孔通风管管道通风系统传热的影响，分析了多孔通风管开孔率、土壤表面温度和土壤表面温度对多孔通风管管道通风系统传热的影响。分析了风速和含水率对多孔通风管壁面对流和蒸发换热的影响，给出了多孔通风管壁面对流和蒸发换热的计算公式，结果表明，冬季通风管的冷却效果主要是对流换热，由于冻土中未冻水较少，蒸发冷却作用较弱，暖季通风管壁与周围空气之间的对流换热会使路基土的温度升高，而由于未冻土壤中未冻水含量大，管壁小孔的蒸发冷却效果显著，因此能够部分或完全平衡由于对流传热引起的路堤中的加热效果，并确保路堤的稳定性。
Convective heat transfer between the air and the pipe wall and evaporative heat removal from the surface of the soil bared in the small holes of the pipe wall are two modes of heat transfer in duct-ventilated embankments with perforated ventilation pipe.The effects of perforating ratio,wind velocity and water content on convective and evaporative heat transfer by the wall of the perforated ventilation pipe are analyzed.The formulae for heat transfer coefficients of convection and evaporation in the perforated ventilation pipe are obtained.The total cooling effect in duct-ventilated embankments during winter is mainly dominated by convective heat transfer due to weak evaporative cooling based on smaller unfrozen water in frozen soils.During warm time,the effect of convective heat transfer between the ambient air and the pipe wall may raise the temperature of the embankment soil,whereas the effect of evaporative cooling by the small holes of the pipe wall is significant due to large unfrozen water content in unfrozen soils,thus being able to partially or completely balance out the heating effect in the embankment due to convective heat transfer and to ensure the embankment stability.