圆台型螺旋能量桩换热性能的数值模拟研究

Numerical Simulation on Heat Transfer Performance of Truncated Cone Helix Energy Pile

圆台型螺旋能量桩是一种换热性能较好的新型地埋管换热器。为探究圆台能量桩的传热规律,采用环形管等效热源替代螺旋管内流体流动传热的数值建模方法,分别建立了0°锥角(圆柱型),5°锥角,10°锥角,15°锥角和20°锥角圆台螺旋能量桩模型,并通过单位面积换热量和单位管长换热量分别从能量桩的整体结构和内部结构进行了传热分析。研究表明,在相同换热管长的情况下,大锥角圆台型螺旋能量桩的整体换热能力比小锥角能量桩更强。通过局部换热分析发现,其上层螺旋管换热能力强于小锥角能量桩,但中间及下层部分的螺旋管换热能力弱于小锥角能量桩。该传热规律可为螺旋能量桩的结构设计、优化提供参考。

The truncated cone helix energy pile(CoHEP)is a new type of environmentally-friendly and cost-effective ground heat exchanger with a strong heat transfer capacity.In order to understand the heat transfer rule,an efficient modeling method that regards a spiral pipe as a series of ring coils is adopted in this paper based on their structural characteristics and makes these ring coils equivalent to heat sources that are based on heat transfer in the pipe.And the CoHEPs of cylindrical energy pile at a cone angle of 0°,5°,10°,15°and 20°are numerically simulated.The heat transfer analysis of the overall structure and internal structure of the energy pile are carried out by heat transfer per unit area and heat transfer per unit pipe length respectively.The results show that CoHEP with a large cone angle exhibits better heat transfer characteristics than that with a small cone angle.And the upper ring coils of the CoHEP with a large cone angle have a stronger heat transfer capacity than that with a small cone angle,while the middle and lower ring coils have a weaker heat transfer capacity through local heat transfer analysis.The results can provide a positive reference for design,optimization of the CoHEP.