取放热不平衡条件下相变材料回填地埋管换热器传热特性研究Study on heat transfer characteristics of ground heat exchanger with PCM backfill under imbalance condition of heat absorption and release
杨卫波,杨彬彬,李晓金
YANG Weibo,YANG Binbin,LI Xiaojin
摘要(Abstract):
为了探讨取放热不平衡条件下相变材料(PCM)回填对地埋管换热器(GHE)传热特性的影响,以混合酸和油酸分别作为夏季与冬季PCM,基于FLUENT软件建立了PCM回填GHE的传热数值模型,分析了PCM相变过程对GHE传热特性的影响,研究了夏、冬季工况下2种PCM不同配比对GHE热响应及PCM相变恢复特性的影响规律。结果表明:从降低土壤温度波动幅度的角度,放热量大于取热量时回填的混合酸比例应大于油酸,反之油酸比例应大于混合酸;从改善土壤温度恢复的角度,应综合考虑运行期间土壤温度变化幅度和恢复期间土壤温度恢复程度;从PCM完成相变角度,夏季和冬季工况下应分别加大混合酸和油酸比例,但就PCM相态恢复而言,夏季和冬季工况下应分别减小混合酸和油酸比例。
In order to investigate the effect of phase change backfill materials on the heat transfer performance of ground heat exchanger (GHE) under the unbalanced heat absorption and release,the mixed acid and oleic acid are selected as the PCM for the summer and winter mode,respectively.A numerical heat transfer model of GHE with PCM backfill is established based on FLUENT software.The influence of phase change process of PCM on heat transfer characteristics of GHE is discussed,and the influence rules of different mix ratios of PCM on thermal response and phase change and recovery characteristics of PCM under summer and winter condition are investigated.The results show that from the perspective of reducing the fluctuation of soil temperature,the proportion of mixed acid should be greater than that of oleic acid when the heat release is greater than the heat absorption,whereas the proportion of oleic acid should be greater than that of mixed acid.From the perspective of improving soil temperature recovery,the extent of soil temperature change during operation and the degree of soil temperature recovery during recovery should be considered comprehensively.From the perspective of PCM phase change,the proportion of mixed acid and oleic acid should be increased in summer and winter conditions respectively.However,in terms of PCM phase recovery,the proportion of mixed acid and oleic acid should be reduced in summer and winter conditions respectively.
关键词(KeyWords):
地埋管换热器;相变材料;传热特性;土壤温度恢复
ground heat exchanger;phase change materials;heat transfer characteristics;soil temperature restoration
基金项目(Foundation): 国家自然科学基金项目(51978599);; 扬州市市校合作基金项目(YZ2019135);; 扬州市重点研发计划(社会发展)项目(YZ2019068)
作者(Author):
杨卫波,杨彬彬,李晓金
YANG Weibo,YANG Binbin,LI Xiaojin
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