摘要
分别建立实际尺寸的单U型和双U型换热器模型,以夏季工况为例用FLUENT软件对其换热过程进行非稳态数值模拟。在热物性、支管间距相同的条件下,以相同流量下单位井深换热量来衡量两种换热器的换热性能。模拟结果表明:单U型和双U型换热器单位井深换热量变化趋势相同———进口温度一定时,随运行时间的增加而趋于稳定;随进口温度的升高而增大;随钻井深度的增大而减小。为保证双U型换热器的换热性能大于单U型换热器且保证机组的运行效率,换热器运行时存在最小和最大流量。对比两种换热器的换热性能可知:双U型换热器的最大流量大于单U型换热器;增大流量和进口温度对双U型换热器换热性能的提高大于单U型换热器;钻井深度不同时,流量的取值范围也不同。
Full-scale 3D numerical model of single U-tube and double U-tube vertical ground heat exchanger （VGHE） were set up, respectively. Take summer operation mode for instance, the CFD software known as FLU- ENT was employed to simulate the heat transfer procedure. The heat exchange performance was compared using the heat flux per depth of borehole at the same flux. The result showed that the heat flux per depth of borehole of two kinds of VGHE has the same change tendency： it tends to be constant with operation time increased when inlet tem- perature is constant; it increases with increasing inlet temperature; it decreases with increasing borehole length. In order to ensure the greater heat exchange performance of double U-tube than single U-tube, and ensure the opera- tion efficiency, there must be a minimum and maximum flux. By comparison of two kinds of VGHE, it can be found that the maximum flux of double U-tube VGHE is greater than single U-tube VGHE; The influence of flux and inlet temperature on heat exchange performance of double U-tube VGHE is greater than single U-tube VGHE ; Borehole length impacts the value range of flux.
出处
《太阳能学报》
EI
CAS
CSCD
北大核心
2012年第7期1193-1198,共6页
Acta Energiae Solaris Sinica
关键词
地源热泵
单U型土壤换热器
双U型土壤换热器
换热性能
ground source heat pump
single U-tube vertical ground heat exchanger
double U-tube vertical groundheat exchanger
heat exchange performance
