Abstract:

Focusing on the problem of high requirements for site selection and groundwater pollution in aquifer energy storage, the construction of artificially filled underground reservoir for energy storage was proposed, and the local flow and heat transfer characteristics in underground reservoir were studied. The conjugate heat transfer model was used to simulate the flow and heat transfer in three kinds of porous media filled with non-uniform particle structure, dodecahedral gradient opening structure and icosahedral gradient opening structure, respectively. The effect of porous media structure on flow and heat transfer characteristics were compared and analyzed. The results indicated that comprehensive heat transfer performance in underground reservoir can be improved by selecting the appropriate filling structure. Among three kinds of porous media, the comprehensive heat transfer efficiency of dodecahedral gradient porous media was the highest. The average Nusselt number of porous media filled with non-uniform particle structure was the largest, but at the same time, the unit pressure drop and friction coefficient were also the largest. With the change of Reynolds number, the Nusselt number of dodecahedral gradient opening structure and icosahedral gradient opening structure intersected. The Nusselt number of icosahedral gradient porous media was larger when Reynolds number was smaller, and the Nusselt number of dodecahedral gradient porous media was larger when Reynolds number was larger.

Key words: aquifer energy storage, artificial reservoir, convective heat transfer, heat transfer in porous media

摘要：

针对含水层储能对选址的要求高且存在地下水污染的问题，提出了构建人工填充储层进行储能，并对储层内的局部流动和换热特性进行了研究。采用共轭传热模型分别对填充非均匀颗粒、十二面体梯度开孔和二十面体梯度开孔结构3种多孔介质孔隙内的流动和换热进行了直接数值模拟，对比分析了多孔介质结构对流动和换热特性的影响。研究发现，通过选择合适的填充介质，储层内的综合换热性能能够得到改善，3种多孔介质中十二面体梯度开孔多孔介质的总换热效率（η）最高；非均匀颗粒多孔介质的平均努塞尔数（Nu_sf）最大，但同时单位压降（∆p/∆x）与摩擦系数（f）也最大；十二面体梯度开孔多孔介质和二十面体梯度开孔多孔介质的Nu_sf随雷诺数（Re）的变化存在交叉，在Re较小时二十面体梯度开孔结构的Nu_sf较大，Re较大时十二面体梯度开孔结构的Nu_sf较大。

关键词: 含水层储能, 人工储层, 对流换热, 多孔介质传热