岩土热物性对深埋管换热性能的影响

Influence of soil thermal properties on heat transfer performance of deep-buried pipes

建立深度为2500m的地埋管-岩土耦合换热模型,对地埋管换热进行2880h(4个月)模拟计算,分析岩土导热系数和地温梯度对地埋管换热特性和岩土温度的影响,探究地埋管累计换热量与影响半径的关系。结果表明:岩土导热系数的增大会提升地埋管的换热能力,但随着导热系数的增大提升速率减缓,导热系数为1 W/(m·K)和4 W/(m·K)时,地埋管在2880h内的平均换热量分别为216.17kW和495.92kW;地温梯度增大同样可以提升地埋管换热能力,且提升速率基本不变,地温梯度为20℃/km和35℃/km时,地埋管在2880h内的平均换热量分别为310.15kW和485.55kW;在换热条件确定时,地埋管累计换热量与受到影响的岩土体积线性相关。

A coupled heat transfer model of buried pipes and soil at a depth of 2500 meters is established.Through the simulation on the heat transfer of buried pipes by 2880 hours(four months),the effects of soil thermal conductivity and geothermal gradient on the heat transfer characteristics of buried pipes and soil temperature.The relationship between the cumulative heat transfer capacity of the buried pipes and the radius of influence is also explored.The results show that an increase in soil thermal conductivity enhances the heat transfer capacity of buried pipes,while the rate of enhancement decreases as the thermal conductivity increases.When the thermal conductivities are 1 W/(m·K)and 4 W/(m·K),the average heat transfer capacities within 2880 hours are 216.17 kW and 495.92 kW respectively.Similarly,an increase in the geothermal gradient also enhances the heat transfer capacity of buried pipes,with a relatively constant enhancement rate.When the geothermal gradients are 20℃/km and 35℃/km,the average heat transfer capacities within 2880 hours are 310.15 kW and 485.55 kW respectively.When the heat transfer conditions are set,the cumulative heat transfer capacity of buried pipes is linearly correlated with the volume of the affected soil.