地源热泵垂直埋管换热器性能的数值模拟研究

Numerical simulation study on performance of vertical borehole heat exchanger

以地源热泵垂直埋管换热器为研究对象,建立地源热泵垂直埋管换热器的三维数值模型,通过实验对数值模型进行验证。利用已建的数值模型分析了埋管内水流流速,水温以及钻孔内不同埋管和回填材料对地埋管换热器性能的影响。研究结果表明:地埋管换热器的单位延米换热量随着回填材料导热系数,管内流速,进口水温,埋管的导热系数的增加而增大;埋管管壁的平均温度随着管内流速,进口水温,埋管的导热系数的增加而增大,但随着回填材料导热系数的增加而减小。

The three-dimensional numerical model of the vertical borehole heat exchanger of ground source heat pump was established and the accuracy of numerical model was verified in this paper.The influences of water flow rate and temperature in buried pipe,pipe materials and backfill materials on the performance of vertical borehole heat exchanger were investigated using the numerical model.The results showed that： the heat transfer rate per meter increased as the thermal conductivity of backfill materials and pipe materials,water flow rate in buried pipe and the temperature at the inlet increased.The temperature at the borehole wall has the same change trend with the influence factors except backfill materials,the temperature at the borehole wall decreased as the thermal conductivity of backfill materials increased.