摘要
基于饱和多孔介质热湿迁移模型,针对不同孔隙度、固体颗粒粒径的两种回填料-碎石和细砂与粘土混和物,对含水层中地埋管换热进行模拟和实验研究。结果表明,在地下水流速较高的砂砾型含水层中,热作用区域集中在来流下游;流速较低的粘土型含水层,不同回填料下的孔壁温差约24h可趋于稳定。据此,可将下游侧支管作为U型管入口以减少热响应测试期间两支管间的热短路,而采用对比实验,有利于在较短的测试时间内获得更准确的地层传热特性。无论是粘土型还是砂砾型含水层,采用孔隙度高、渗透性好的碎石进行回填,有利于钻孔内的对流换热。在饱和粘土层中,以碎石进行回填时,取热工况下单位井深换热量较细砂与粘土混和物回填提高5%～10%,排热工况下提高10%～15%。
The effects of backfill on the heat transfer performance of underground U-shaped exchanger were studied based on the model for convection in saturated porous media. The results indicate measures that can be expected to improve the accuracy of thermal response test in gravel-like aquifer and clay-like aquifer, respectively. Backfills with high poreusity and permeability is prefered to compacting materials when the U-shaped exchanger is applied to aquifer strata where eonv- ecion heat transfer is dominant. A field test was carried out to detennine the heat exchange capacity of U-shaped exchanger installed in clay-like aquifer with crushed stone backfill, and an enhancement of 5% - 10% and 10% - 15% was observed under heat extracting and heat emitting mode, respectively.
出处
《太阳能学报》
EI
CAS
CSCD
北大核心
2009年第5期572-576,共5页
Acta Energiae Solaris Sinica
基金
国家科技支撑计划(2006BAJ03A06)
国家重点基础研究(863)发展计划(2007AA05Z432)
关键词
回填料
含水层
对流换热
U型埋管换热器
backfill
aquifer strata
convective heat transfer
underground U-shaped exchanger
