单U形地埋管换热特性及热作用半径数值分析

Numerical Analysis on Heat Transfer Characteristics and Thermal Effect Radius of the U-shaped Buried Tube

针对影响U形地埋管换热能力及热作用半径的典型因素,采用模拟分析,得到了不同入口水温、管内流量、回填料导热系数、岩土体导热系数、体积热容条件下,埋管单位井深换热量和平均热作用半径随之变化的规律。结果表明:地埋管的换热量与入口温度、岩土体导热系数及单位体积热容呈线性变化,与入口流量和回填料导热系数呈指数形式变化,通过拟合分析出单位井深地埋管日平均换热量与五个因素的回归方程;在热物性参数中热扩散系数对地埋管的平均热作用半径影响最显著。

Typical influencing factors on heat transfer capacity and thermal effect radius of the U-shaped buried tube are simulated and analyzed to gain the heat transfer on depth and the changing rules about thermal effect radius,under various inlet temperature,flow rate,thermal conductivity coefficient of backfill,thermal conductivity coefficient of rock and soil mass. The results show that the heat transfer of the buried pipe change linearly with the inlet temperature,the thermal conductivity of rock and soil,and the heat capacity per unit volume,and the heat transfer of the buried pipe changes exponentially with the inlet flow rate and the thermal conductivity of the backfill; Daily average heat transfer of the buried pipe on depth and the regression equations of the five factors are obtained through regression analysis; In the thermophysical parameters,the thermal diffusivity has the most significant influence on the mean radius of thermal effect for the heat pipe.