抽-灌井水量对耦合式地埋管井群传热性能的影响

基于多孔介质传热、传质理论以及有限长线热源模型,建立耦合式地埋管换热器井群热-渗数学模型,以原位热响应试验与现场抽水试验为验证依据。针对渤海盆地含水层,通过数值模拟探究不同抽-灌水量对地埋管井群传热性能的影响。研究表明:随着抽-灌水量的增大,地埋管井群换热能效系数增大,井群下游区域热影响范围扩大。在制冷与供热工况下,井孔E7所在细砂层佩克莱特数(Pe)与单位埋深换热变换量Δq关系曲线均呈高斯函数分布。基于所建耦合式地埋管井群物理模型,抽-灌水量推荐范围为400~600 m3/d。

INFLUENCE OF QUANTITY OF PUMPING AND INJECTION WELLS ON HEAT TRANSFER CHARACTERISTIC OF COUPLING BOREHOLE HEAT EXCHANGERS

A three-dimensional unsteady state numerical model coupled heat transfer and groundwater seepage for borehole heat exchangers(BHEs)is established,based upon the thermal and mass transfer theory in porous media and the transient finite line heat source model. The coupled model is validated by the data determined the in-situ thermal response test and the pumping test. Taking the aquifer in Bohai Bay Basin as the research object,the numerical simulation is probed into the influence of the water quantity of pumping and injection wells on heat transferring characteristics of BHES. The results show that the heat transfer efficiency coefficient increases significantly while the quantity of pumping and injection water guantity increases,so that the thermal effective radius is enhanced obviously in the downstream area of BHEs. The relation curves between the variation of heat transfer rate per unit depth of the BHE E7 and Peclet(Pe)in the cooling and heating season appear the Gauss function distribution. It is recommended that the reasonable range of the quantity of pumping and injection is from 400 to 600 m^3/d according to the coupling BHEs physical model.