地埋管换热系统中土壤温度恢复特性分析
Soil-temperature recovery characteristics of ground heat exchange system
摘要：
针对防护工程负荷特点，基于温度场叠加原理建立了考虑轴向传热的纯导热介质和考虑地下水流动的土壤温度恢复模型。利用所建立的纯导热模型，对不同深度、径向距离、运行方式及地埋管热流密度下土壤温度恢复过程进行了分析。研究了地下水流动对土壤温度恢复的影响及地埋管的热作用距离。结果显示：地表及轴向传热对土壤温度恢复的影响不可忽略；土壤温度恢复率随着与埋管距离的增大和运行周期的延长而降低，随地下水流速的增大而升高；土壤温度恢复特性与岩土物性、室外气象参数、系统运行方式等有关，而与地埋管热流密度无关；在冷热负荷不平衡的地区布置地埋管时应适当增大埋管间距。
Abstract：
Develops two kinds of soil-temperature recovery models with and without considering the axial heat transfer and the influence of groundwater flow by the superposition principle of temperature field, which are for the load in protective engineering. Analyses the soil temperature recovery process by the pure conductive model with different depths, radii, operation modes and heat flow densities. Studies the influence of groundwater flow on the soil-temperature recovery process and heat affecting distance.The results show that the influences of ground surface temperature and heat transfer along the borehole are non-negligible to soil-temperature recovery. Soil-temperature recovery rate decreases with the increase of distance and operating cycle, while it increases with the groundwater flow velocity. Soil-temperature recovery rate has correlation with soil properties, outdoor meteorological parameters, system operation modes and so on, while it is independent on the heat flow density. For load imbalance area, the borehole spacing should be appropriately increased.
Keywords:buried pipe, soil-temperature recovery characteristic, pure conduction, groundwater flow, model