摘要
超长重力热管(SLGHP)因其优异的热传输能力和无泵驱动的特点,在地热能开发领域展现出广阔的应用前景。然而,在实际应用中,SLGHP的启动过程涉及复杂的气液相变与传热机制,尤其是工质注入后的温度响应及热力平衡过程尚不明确。结合实验测量与数值模拟,研究了SLGHP-热泵供暖系统的注液启动过程、取热启动特性及热泵启动方式对系统运行性能的影响。实验采用光纤测温技术实时监测注液过程中管壁温度的动态演变,发现氨工质自上而下润湿过程中形成的温度转折点与工质注入深度高度关联,可作为工质分布的动态指示参数。注液完成后,热管轴向温度梯度由初始的18.4℃/km降至2℃/km,均温性显著提升。数值模型与实验结果误差小于3%,验证了工质分布与温度场演化预测的可靠性。此外,提出了基于注液完成12 h后井口蒸汽温度与地层平均温度偏差的工程判据,无须额外布设管外测温装置即可评估注液启动阶段完成状态。进一步分析表明,热泵冷启动时,排气压力由0.55 MPa升至1.06 MPa,供暖量1 h内达900 kW,性能系数(COP)稳定于6.5;而热泵热启动过程由于系统残余热量,系统达到相对稳定所需时间缩短28%。本研究揭示了SLGHP-热泵系统启动阶段的传热机制,为SLGHP地热系统的优化设计与稳定运行提供参考。
energy development due to its excellent heat transfer capacity and pump-free drive characteristics. However, in practical applications, the start-up process of SLGHP involves complex phase change and heat transfer mechanisms, especially regarding the temperature response and thermal equilibrium following working fluid injection, which remain inadequately understood. This study investigates the liquid-injection start-up process, heat extraction start-up characteristics, and the influence of heat pump start-up modes on the operational performance of the SLGHP-heat pump heating system through combined experimental measurements and numerical simulations.Fiber optic temperature sensing was employed to monitor the dynamic evolution of wall temperature during the injection process. The results indicate that the temperature inflection point formed during the downward wetting of ammonia correlates strongly with the injection depth and can serve as a dynamic indicator of fluid distribution.Upon completion of injection, the axial temperature gradient of the heat pipe decreases from 18.4C/km to 2C/km,significantly improving thermal uniformity. The numerical model exhibits less than 3% deviation from experimental data, validating the predictive accuracy of working fluid distribution and temperature field evolution. Moreover, an engineering criterion based on the temperature deviation between wellhead vapor and formation average temperature after 12 h of injection is proposed, enabling assessment of the start-up completion without the need for external temperature sensors. Further analysis reveals that during cold start-up, the discharge pressure of the heat pump increases from 0.55 MPa to 1.06 MPa, with heating output reaching 900 kW within 1 h and a COP stabilizing at 6.5. In contrast, during thermal start-up, the presence of residual thermal energy in the system shortens the time required to reach a relatively stable state by 28%. This study elucidates the heat transfer mechanism during the start-up phase of the SLGHP-heat pump system, providing valuable insights for the optimized design and stable operation of SLGHP geothermal systems.
作者
王宾
李子豪
黄文博
陈娟雯
李昂
党鹏飞
蒋方明
WANG Bin;LI Zihao;HUANG Wenbo;CHEN Juanwen;LI Ang;DANG Pengfei;JIANG Fangming(Guangzhou Institute of Energy Conversion,Chinese Academy of Sciences,Guangzhou 510640,Guangdong,China;CAS Key Laboratory of Renewable Energy,Guangzhou 510640,Guangdong,China;Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development,Guangzhou 510640,Guangdong,China;School of Mechanical and Power Engineering,Shenyang University of Chemical Technology,Shenyang 110142,Liaoning,China;School of Energy Science and Engineering,University of Science and Technology of China,Hefei 230026,Anhui,China)
出处
《化工学报》
北大核心
2025年第10期5035-5046,共12页
CIESC Journal
基金
国家重点研发计划项目(2021YFB1507300,2021YFB1507301)
国家自然科学基金项目(52206126,52206287)
广州市科技计划项目(SL2023A04J01976)。
关键词
超长重力热管
地热能
启动特性
相变传热
热泵冷热启动
super-long gravity heat pipe
geothermal energy
start-up characteristics
phase-change heat transfer
cold and thermal start-up of heat pump
作者简介
通信作者:陈娟雯(1989—),女,博士,副研究员,chenjw@ms.giec.ac.cn;通信作者:蒋方明(1973—),男,博士,研究员,jiangfm@ms.giec.ac.cn;第一作者:王宾(1998—),男,硕士,a626954940@163.com。
