地埋管换热器周围非饱和土壤热湿迁移数值模拟

本文在极坐标下建立了地埋管换热器周围非饱和土壤的热湿迁移数学模型与纯导热数学模型，采用有限体积法对两种模型进行了数值求解。模拟结果表明，向土壤中排热会使得钻孔壁附近的含湿量降低。当土壤初始含湿量较大时，土壤中湿分迁移对土壤热物性基本上没有影响，纯导热模型与热湿迁移模型模拟土壤与地埋管换热器之间的换热现象时基本一致；当土壤初始含湿量较小时，热作用对钻孔壁附近的湿迁移影响较为显著，土壤热物性会随之发生变化，此时纯导热模型与热湿迁移模型计算差值较大。

The Numerical Simulation of Heat and Moisture Transfer in Unsaturated Soil around the Ground Heat Exchanger

A numerical Heat and Moisture Transfer Model （HMTM） and a Pure Conduction Model （PCM） were established separately for unsaturated soil around the Ground Heat Exchanger （GHE） and were numerically solved by finite volume method. The simulation results indicate that rejecting heat into soil can reduce moisture content in the vicinity of the borehole wall. When the initial moisture content is high, moister transfer has little effect on soil thermal properties. In this case, the results of the HMTM and the PCM are basically identical. On the contrary, when the initial moisture content is low, the thermal effect has significant influence on moisture transfer around the borehole wall, and the soil thermal properties will change correspondingly. In this case, there is a large difference between the results of these two models.