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建立了考虑土壤冻结的地埋管换热器非稳态传热模型,采用有限容积法离散了管内流体、管壁及土壤区域的控制微分方程,对涉及的土壤相变问题采用显热容法处理。数值计算结果表明,地埋管换热器周围土壤冻结区域较小,但土壤冻结后导热系数大幅度提高,更有利于土壤的导热;考虑土壤冻结的影响后,计算出的地埋管换热器的出水温度和取热量均有所提高;土壤含水量高有利于地埋管换热器的换热,但土壤含水量较低时,土壤冻结对地埋管换热器性能的影响较小。
The unsteady heat transfer model of ground tube heat exchangers considering soil freezing is established. The governing differential equations of fluid, pipe wall and soil are discretized by finite volume method. The sensible heat capacity method deal with. The numerical results show that the soil freezing area around the heat exchanger is small, but the thermal conductivity of the soil after freezing greatly increases, which is more conducive to the soil thermal conductivity. After considering the soil freezing effect, The outlet water temperature and the calorific value increased; the high soil water content was beneficial to the heat transfer of the buried tube heat exchanger, but the soil freezing had a less effect on the performance of the ground tube heat exchanger when the soil water content was lower .