外置双U型静钻根植工法能源桩换热性能研究?

为探究外置双U型静钻根植工法能源桩换热性能,通过现场热响应试验,利用热源理论初步分析其岩土综合导热系数,建立三维传热数值模型并进行验证。利用三维传热数值模型分析换热管间距及其导热系数、换热液流速和桩周水泥土导热系数等因素对该新型桩换热性能的影响。分析结果表明,试桩区域岩土综合导热系数为1.64W(m·K)-1。提高换热管间距、换热管导热系数、换热液流速和桩周水泥土导热系数均能提高能源桩的换热性能,但当换热管间距大于0.25 m,换热液流速达到紊流态,换热管和桩周水泥土导热系数高于岩土综合导热系数后,提高上述参数对能源桩换热性能的提高贡献不大。

Heat Transfer Performance Analysis of Static Drill Rooted Geothermal Energy Piles with External Double U-tubes

In order to explore the heat transfer performance of the Static Drill Rooted Energy Pile(SDREP),an equivalent thermal conductivity of the ground was investigated by using heat source theory based on the field thermal response test.A three-dimensional heat transfer numerical model of the energy pile was established and verified,and the influences of the tube spacing and its thermal conductivity,the fluid velocity,and the thermal conductivity of cement-soil around the pile on the heat transfer performance of the SDREP were analyzed.The results show that the ground equivalent thermal conductivity is 1.64 W(m·K)-1.The heat transfer performance of the energy pile can be improved by increasing the spacing of the heat exchange pipe and its thermal conductivity,the fluid velocity,and the thermal conductivity of soil-cement around the pile.However,when the tube spacing is over0.25 m,the fluid velocity reaching a turbulent state,or the thermal conductivity of tube and cementsoil is higher than that of the ground,there is little contribution to improve the heat transfer performance of the energy pile.