单/双U形地埋管换热器传热特性模拟研究  

Simulation study on heat transfer characteristics of vertical single/double U-tube buried heat exchanger

作　　者：刘鹏 刘卫 朱超群 张德瑜 徐博荣 LIU Peng;LIU Wei;ZHU Chao-qun;ZHANG De-yu;XU Bo-rong

机构地区：[1]西安万科企业有限公司,陕西西安710068 [2]陕西省建筑设计研究院(集团)有限公司,陕西西安710018 [3]西安华建工程设计股份有限公司,陕西西安710005

出　　处：《节能》2022年第10期40-45,共6页Energy Conservation

摘　　要：为了研究不同因素对单/双U形地埋管换热器传热特性的影响,建立单U形和双U形地埋管换热器传热物理数学模型,分析流体进口流速、流体进口温度、回填材料和土壤竖向温度梯度对地埋管周围土壤温度分布规律和单位管长换热量的影响。结果表明:地埋管周围土壤温度随流速的增加而增加且双U形大于单U形,对径向距离大于1 m的土壤基本无影响;双U形地埋管换热器的单位管长换热量大于单U形,双U形地埋管换热器的热短路现象更严重;增加流体进口温度时,土壤温度、单位管长换热量均增加,但热作用范围基本不受影响;回填材料为砾砂时的土壤温度增加幅度大于黏土,单位管长换热量大于黏土,但增加比例小于回填材料为黏土时的情况;土壤竖向温度梯度越大,土壤温度和单位管长换热量波动幅度越剧烈,且双U形的波动幅度大于单U形;钻井深度和土壤竖向温度梯度较大时,地埋管不宜采用U形管作为换热器。研究结果对单/双U形地埋管换热器的设计及地源热泵系统的运行提供参考。In order to study the influence of different factors to heat transfer characteristics of single/double U-tube buried heat exchanger, the paper established the physical mathematical model of heat transfer of single/double U-tube buried heat exchanger, and analyzed the influence of fluid inlet velocity, fluid inlet temperature, backfill material and soil vertical temperature gradient to soil temperature around the buried pipe distribution rule and the heat transfer per unit length. The result shows that the soil temperature around the buried pipe increases with the increase of flow velocity, and the double U is larger than the single U, which has no effect on the soil beyond the range of 1 m radial distance. The unit pipe length of the double U is larger than the single U, and the thermal short circuit of the double U is serious. Soil temperature and heat transfer per unit pipe length increase with the increase of fluid inlet temperature, but the heat action range is not affected by the increase. When the backfilling material is gravel sand, the increase of soil temperature is greater than that of clay, and the heat transfer per tube length of gravel sand is greater than that of clay. But the increase proportion is less than the situation when the backfill material is clay. The larger the vertical soil temperature gradient is,the more severe the fluctuation range of soil temperature and heat transfer per unit pipe length is, and the fluctuation range of double U is larger than that of single U. When the drilling depth and soil vertical temperature gradient are large, it is not suitable to use U-tube as heat exchanger for buried pipe. The research results provide a reference for the design of single/double U-tube buried heat exchanger and the operation of ground source heat pump system.

关 键 词：地源热泵 单/双U形地埋管换热器 单位管长换热量 间歇运行 回填材料 

分 类 号：TU83[建筑科学—供热、供燃气、通风及空调工程]