环形均匀分布桩群应用螺旋埋管换热器的数值模拟

Numerical simulation of spiral buried pipe heat exchangers applied to annular uniformly distributed pile groups

采用数值模拟的方法,研究了流体流速、进口水温、螺旋管管径、螺距4个参数对桩基埋管换热器出口水温和传热量的影响及周围区域土壤温度动态分布特征。结果表明:桩基埋管换热器的传热量随着流体流速的增大,先不断增大,当流速过大时,传热量开始减小;进口水温为32.5-35.0℃时,传热量与进水温度近似呈线性关系,提高进口水温,能够增大传热量;螺旋管管径32 mm的桩基埋管换热器的传热量比管径25 mm的大5.8%;500 mm螺距的桩基埋管换热器的传热量较300,400 mm螺距的分别增大1.7倍和1.2倍,换热效果大幅提高。

By the method of numerical simulation,studies the effects of fluid velocity,inlet water temperature,spiral pipe diameter and pitch size on the outlet water temperature and heat transfer of pilefoundation buried pipe heat exchangers and the dynamic distribution characteristics of surrounding soil temperature.The results show that the heat transfer capacity of pile-foundation buried pipe heat exchangers increases firstly when the fluid velocity increases and then decreases when the fluid velocity exceeds a certain point.When the inlet water temperature is 32.5 to 35.0℃,the heat transfer is almost linearly proportional to the inlet water temperature,and the higher the inlet water temperature,the higher the heat transfer capacity.The heat transfer capacity of pile-foundation heat exchanger with spiral pipe diameter of 32 mm is 5.8%higher than that of pipe diameter of 25 mm.The heat transfer capacity of the pile-foundation heat exchanger with a pitch size of 500 mm is 1.7 times higher than that with 300 mm pitch size and 1.2 times higher than that with 400 mm pitch size,which indicates a significant enhancement of heat transfer efficiency.