土壤蓄热-放热过程中地埋管周围土壤温度特性模拟
发布时间：2018-10-17 10:22
【摘要】：为探索内蒙中部地区地源热泵蓄热-放热过程中地埋管周围土壤温度变化特性,以垂直U型地埋管周围土壤为研究对象,基于有限元分析法建立了二维非稳态传热物理数学模型。在与试验结果进行验证的基础上,对土壤蓄热、放热和蓄热-放热耦合过程进行模拟研究。分析了热作用半径、单位管长换热量和土壤温度随热泵运行时间及运行模式的变化规律;单一条件下的蓄热、放热以及蓄热-放热耦合模式下土壤热平衡问题,探讨了流体入口流速、温度、土壤类型和热泵运行模式等因素对土壤温度场的影响。研究结果表明:热作用半径随蓄热时间的增加而增大且逐渐趋于平缓,热泵运行25和28 d后,热作用半径分别为3.3和3.4 m;流体入口温度对热作用半径及单位管长换热量影响较大但流体流速影响较小,流体入口温度和速度分别为40、60℃和0.6、1.2 m/s时,对应热作用半径分别为3.7、4.5和3.5、3.6 m。合理的间歇运行模式对换热量及埋管周围土壤温度的恢复均有改善;土壤导热系数越大土壤温度恢复时间与效果越佳,土壤导热系数为3.1 W/(m?K)时恢复后温度为9.3℃(土壤初温9.5℃)。此外,蓄热-放热耦合模式下换热量不等对土壤热平衡具有较大影响。试验验证表明,所建模型具有一定的准确性其相对最大误差为5.35%。
[Abstract]:In order to study the soil temperature change around the buried pipe in the process of heat storage and heat release of ground-source heat pump in the central part of Inner Mongolia, the soil around the vertical U-type buried pipe is taken as the research object. Based on finite element analysis, a two-dimensional unsteady heat transfer physical mathematical model is established. Based on the experimental results, the soil heat storage, heat release and heat storage coupled with heat release were simulated. The variation law of heat action radius, heat transfer per unit tube length and soil temperature with heat pump operation time and operation mode are analyzed, and the heat storage, heat release and soil heat balance under a single condition are analyzed. The effects of fluid inlet velocity, temperature, soil type and heat pump operating mode on the soil temperature field are discussed. The results show that the heat action radius increases with the increase of heat storage time and tends to be gentle. After 25 and 28 days of heat pump operation, The thermal action radius is 3.3 and 3.4 m.The fluid inlet temperature has great influence on the thermal action radius and heat transfer rate per unit tube length, but the influence of fluid flow velocity is small. When the fluid inlet temperature and velocity are 40 ~ 60 鈩，
本文编号：2276352
[Abstract]:In order to study the soil temperature change around the buried pipe in the process of heat storage and heat release of ground-source heat pump in the central part of Inner Mongolia, the soil around the vertical U-type buried pipe is taken as the research object. Based on finite element analysis, a two-dimensional unsteady heat transfer physical mathematical model is established. Based on the experimental results, the soil heat storage, heat release and heat storage coupled with heat release were simulated. The variation law of heat action radius, heat transfer per unit tube length and soil temperature with heat pump operation time and operation mode are analyzed, and the heat storage, heat release and soil heat balance under a single condition are analyzed. The effects of fluid inlet velocity, temperature, soil type and heat pump operating mode on the soil temperature field are discussed. The results show that the heat action radius increases with the increase of heat storage time and tends to be gentle. After 25 and 28 days of heat pump operation, The thermal action radius is 3.3 and 3.4 m.The fluid inlet temperature has great influence on the thermal action radius and heat transfer rate per unit tube length, but the influence of fluid flow velocity is small. When the fluid inlet temperature and velocity are 40 ~ 60 鈩，
本文编号：2276352
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