摘要
为提高中深层地热开发效率,基于吉林松原场地实际工程,建立一种内插螺旋叶片间距d分别为300mm、200mm的小尺度改进型同轴套管换热器数值模型,通过施加热流密度开展改进型换热器传热机理研究。结果表明,在雷诺数Re=6000~20000的湍流状态下,增大循环流速可以强化换热器的传热性能。通过改变换热器中流体的流动状态,减薄热边界层,进而加大换热器与岩土体的热传导能力,提高热采率。相对于光滑内管,当螺旋叶片间距d为300 mm时,努塞尔数Nu提升了11.0%~14.6%,对流换热系数h_(f)为普通换热器的1.07~1.15倍;当d为200 mm时,Nu提升了17.3%~28.1%,h_(f)为普通换热器的1.17~1.28倍。该研究可为下一步开展实际工程、提高地热能开采效率提供理论支撑。
In order to improve the efficiency of medium-deep geothermal development,a numerical model of a small-scale improved coaxial casing heat exchanger with spiral blades with interpolation spacing d of 300 and 200 mm wasestablished based on the actual engineering of the Songyuan site in Jilin,and the heat transfer mechanism study of the improved heat exchanger wascarried out by applying heat flow density.The results show that the heat transfer performance can be enhanced by increasing the circulating flow rate under the turbulent flow condition of Re=6000-20000.By changing the flow state of the fluid in the heat exchanger,the thermal boundary layer is thinned,which in return increasesthe heat transfer capacity between the heat exchanger and the geotechnical body and improvesthe heat recovery rate.Compared with the smooth inner tube,Nu is improved by 11.0%-14.6%and h_(f)is 1.07-1.15 times when the spiral blade spacing d is 300 mm;Nu is improved by 17.3%-28.1%and hf is 1.17-1.28 times when the spiral blade spacing d is 200 mm.The study may provide theoretical support for the next step of practical engineering to improve geothermal energy extraction.
作者
娄俊庆
高孟秋
万里宁
李剑波
张奇
张延军
LOU Junqing;GAO Mengqiu;WAN Lining;LI Jianbo;ZHANG Qi;ZHANG Yanjun(China Power Engineering Consulting(Group)Corporation Northeast Electric Power Design Institute,Changchun 130033,China;College of Construction Engineering,Jilin University,Changchun 130026,China)
出处
《新能源进展》
CSCD
2023年第4期374-380,共7页
Advances in New and Renewable Energy
基金
中国能源建设集团规划设计有限公司科技项目(GSKJ2-G02-2021)
国家自然科学基金项目(41772238)。
关键词
地热能
强化换热
改进型换热器
同轴换热器
螺旋叶片
geothermal energy
enhanced heat transfer
improved heat exchanger
coaxial heat exchanger
spiral blade
