摘要
为了解中深层U型地热井的取热性能,本文以河北工程大学新校区建立的2500m深U型地热井为研究对象,建立了中深层U型地热井传热的数学物理模型。模型考虑了当地岩土体地温梯度和岩性变化对传热性能的影响,模拟所得数据利用实际工程测量数据进行验证。仿真结果可以看出合理降低入口温度可以增加取热量,入口温度每降低1℃,地热井取热量增加约40kW。合理增加循环工质流速可以增加取热量,但取热量增量逐渐降低。本研究中,当采出井段保温长度保持定值时,采用导热系数为0.02W/(m·K)的保温材料地热井取热量和出口温度最大。同样,当选取保温材料一致时,地热井取热量和出口温度随保温长度的增加而增加。与实际工程相比,井底取热管长度为1000m时,地热井取热量和出口温度分别增长122.32kW和1.56℃;当钻井深度为5000m时,地热井出口温度增长6.35℃。仿真结果表明合理降低入口温度,提升流速,增加井底取热管长度,增加钻井深度,增加采出井段保温长度和采用低导热系数保温材料,可以有效提升深U型地热井取热量和出口温度。研究结果可为中深层U型地热井井下换热系统的优化提供参考。
To understand the heat transfer performance of the middle-deep U-bend geothermal well,the 2500 m deep U-bend geothermal well was taken as the research object at the Hebei University of Engineering.This study established a mathematical and physical model of heat transfer in a U-bend geothermal,and the influence of geothermal gradient and lithologic changes on heat transfer performance was considered.The established model was verified based on the experimental data.Numerical simulation results show that a reasonable reduction of inlet temperature can increase thermal power.The thermal power of the geothermal well will increase by about 40 kW for every 1°C reduction of inlet temperature.The thermal power can be increased with a reasonable increase in theflow rate of the circulatingfluid,but the increment of the thermal power decreases gradually.The simulation results show that the thermal power and outlet temperature of a deep U-bend geothermal well can be effectively improved by appropriately reducing the inlet temperature,increasing theflow rate,increasing the collection length,increasing the well depth,increasing the insulation length of the vertical well section and using low thermal conductivity insulation materials.The research results from this study could provide a reference for the heat transfer system optimization of the middledeep U-bend geothermal well.
作者
鲍玲玲
李俊岩
郭海明
Niu Guo-Qing
Wang Zhe
Zhang Yao
Wang Yu-Sen
Bao Ling-Ling;Li Jun-Yan;Guo Hai-Ming;Niu Guo-Qing;Wang Zhe;Zhang Yao;Wang Yu-Sen(School of Energy and Environmental Engineering,Hebei University of Engineering,Handan 056038,China;Handan Shengda Energy Technology Co.,Ltd,Hebei Handan 056004,China)
基金
support of the Science and Technology Research project of Hebei University(Grant No.ZD2018088)
sponsored by the Natural Science Foundation of Hebei Province(E2020402052)
the Key R&D Projects in Hebei Province(20374503D).
关键词
中深层U型地热井
传热模型
数值模拟
地热井取热量
地热井出口温度
middle-deep U-bend geothermal well
heat transfer model
numerical simulation
thermal power
outlet temperature.
