地源热泵U型管地下换热器的CFD数值模拟

为了给地源热泵U型管地下换热器的优化设计提供理论依据,通过CFD数值软件对地源热泵U型管地下换热器系统中的流动和传热过程进行数值模拟.结果表明,地源热泵U型管地下换热器的换热效率随支管间距的增大而增加,随回填土材料热导率的增加而增大,而且支管间距和回填土材料热导率对换热器效率的影响是很复杂的非线性关系.当钻孔深度超过80m时,两支管的温升比急剧增加,支管间的热损失加剧,建议在实际操作中钻孔深度不要太深.

CFD numerical simulation of a U-tube ground heat exchanger used in ground source heat pumps

To provide a theory for the optimized design of a U-tube ground heat exchanger used in ground source heat pumps, CFD software was used to simulate the processes of flow and heat transfer in the U-tube ground heat exchanger. The results show that the heat transfer efficiency of the U-tube ground heat exchanger increases with the increasing distance between two tubes and with the increasing heat conductivity of backfilling soil. The effect of the distance between two tubes and the heat conductivity of backfilling soil on the U-tube ground heat exchanger's efficiency are a very complex nonlinear relation. When the hole-depth is deeper than 80 m, the temperature rise ratio of two tubes increases rapidly and the heat losing between two tubes increases. In practical operation, the hole-depth is better not to be too deep.