岩溶构造对地埋管群换热效率影响数值模拟研究

穆玄; 裴鹏; 周鑫; 屠洪盛

doi:10.12363/issn.1001-1986.21.09.0513

岩溶构造对地埋管群换热效率影响数值模拟研究

doi: 10.12363/issn.1001-1986.21.09.0513

穆玄^1,,
裴鹏^1,*, ,,
周鑫²,
屠洪盛³

1.
贵州大学矿业学院，贵州贵阳 550025
2.
国网北京市电力公司电力建设工程咨询分公司，北京 100000
3.
中国矿业大学矿业工程学院，江苏徐州 221116

基金项目: 国家自然科学基金地区项目(52066005)；贵州省科技支撑计划项目(黔科合支撑〔2020〕2Y025)

详细信息

第一作者:
穆玄，1993年生，男，贵州遵义人，硕士研究生，从事浅层地热方向研究. E-mail：1227626643@qq.com

通信作者:
裴鹏，1982年生，男，贵州贵阳人，博士，教授，从事浅层地热能开发方面的研究. E-mail：ppei@gzu.edu.cn

中图分类号: TU83
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- 被引次数: 0
出版历程
- 收稿日期: 2021-09-14
- 修回日期: 2021-12-29
- 刊出日期: 2022-10-25
- 网络出版日期: 2022-10-10

Numerical simulation of the influence of karst structure on heat transfer efficiency of buried pipeline group

MU Xuan^1
,,
PEI Peng^{1,*
, ,},
ZHOU Xin²,
TU Hongsheng³

1.
College of Mining, Guizhou University, Guiyang 550025, China
2.
Power Construction Engineering Consulting Branch of State Grid Beijing Electric Power Company, Beijing 100000, China
3.
College of Mining Engineering, China University of Mining and Technology, Xuzhou 221116, China

Funds: National Natural Science Foundation of China Regional Project (52066005); Guizhou Province Science and Technology Support Program (Qianke He Support [2020] 2Y025; Guizhou Education Department Young Science and Technology Talent Growth Project (Qian Jiao He KY [2017] 117).

摘要

摘要: 地埋管是岩体热泵系统与地层直接交换冷热量的部分。岩溶地区含水构造复杂多样，对地埋管群换热储热有明显影响。对27根垂直地埋管群在无岩溶构造、岩溶裂隙构造、岩溶管道构造以及混合岩溶构造4种地质构造类型中的换热过程进行了模拟，并对比了岩体内温度场、埋管出口水温、热泵机组制冷系数(COP)以及单位井深换热量等参数的变化。结果表明：在制冷工况下，不同模型温度场中，岩体中存在岩溶裂隙构造或岩溶管道构造时，地下水流动对岩体热堆积有明显缓解作用；岩溶导水构造与地埋管的距离也是重要影响因素。模型运行到第1个制冷周期末期时，含岩溶裂隙构造岩体和含岩溶管道构造岩体的进出口水温差比混合岩溶构造岩体的分别升高了0.87、4.00 K；无岩溶构造岩体进出口水温差比混合岩溶构造岩体的下降了1.16 K。无岩溶构造岩体、岩溶裂隙构造岩体、岩溶管道构造岩体和混合岩溶构造岩体的COP分别为7.2、7.4、7.8和7.3；单位井深换热量分别为64.1、90.3、130.7和79.1 W/m。研究结果表明，岩溶导水构造明显增强了地埋管群的换热效率，不同的地质构造类型对地埋管换热效率的影响也不一样。
- 换热效率 /
- 岩溶构造 /
- 地源热泵 /
- 数值模拟
Abstract: The buried pipeline is the part where the rock mass heat pump system performs direct heat transfer with the ground. The water-bearing structure in the karst area is complex and diverse, which has a significant impact on the heat transfer and storage of the buried pipeline group. Herein, the heat transfer process of a group of 27 vertical buried pipelines in four geological structure types was simulated, including the non-karst structure, fractured karst structure, karst conduit structure and mixed karst structure. Meanwhile, comparison was made for the change of parameters, such as the temperature field in the rock mass, the outlet water temperature of buried pipeline, the coefficient of performance (COP) of heat pump unit, and the heat change in unit well depth. The results show that the flow of groundwater can significantly relieve the heat build-up in the rock mass where fractured karst structure and karst conduit structure exist in different model temperature fields under the refrigeration conditions, and the distance between the karst water-conducting structure and the buried pipeline is also an important influencing factor. When the model operates to the end of the first refrigeration cycle, the temperature difference between the inlet and outlet of rock mass in fractured karst structure and karst conduit structure is 0.87 K and 4.00 K higher than that in mixed karst structure respectively, while the temperature difference between the inlet and outlet of rock mass in non-karst structure is 1.16 K lower than that in mixed karst structure. The COPs of rock mass in non-karst structure, fractured karst structure, karst conduit structure, and mixed karst structure are 7.2, 7.4, 7.8 and 7.3 respectively. Besides, the heat transfer per well depth is 64.1, 90.3, 130.7 and 79.1 W/m respectively. The research results show that the karst water-conducting structure significantly enhances the heat transfer efficiency of the buried pipeline group, and different geological structure types have different effects on the heat transfer efficiency of the buried pipeline.
- heat transfer efficiency /
- karst structure /
- ground source heat pump /
- numerical simulation

HTML全文

图 1 4种岩溶构造模型

Fig. 1 4 karst structural models

下载: 全尺寸图片幻灯片

图 2 4种岩溶构造网格划分

Fig. 2 Grid division of 4 types of karst structures

下载: 全尺寸图片幻灯片

图 3 热响应进出口水温与模拟进出口水温对比

Fig. 3 Comparison of thermal response outlet water temperature and simulated outlet water temperature

下载: 全尺寸图片幻灯片

图 4 4种岩溶构造模拟温度场剖视图

Fig. 4 Cross-sectional view of simulated temperature field of four karst structures

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图 5 4种岩溶构造模拟温度场俯视图

Fig. 5 Top view of simulated temperature field of 4 karst structures

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图 6 4种岩溶构造第2个制冷期(第24个月末)模拟温度场剖视图

Fig. 6 Cross-section view of simulated temperature field of 4 karst structures during the second shutdown period(end of the 24th month)

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图 7 地埋管与岩溶管道构造温度场剖视图

Fig. 7 Cross-sectional view of the temperature field of the buried pipe and the karst pipeline

下载: 全尺寸图片幻灯片

表 1 模拟设计参数

Table 1 Simulation design parameters

参数	数值
U型管内径/mm	26
U型管外径/mm	32
U型管壁厚/mm	3
U型管管壁导热系数/(W·m⁻¹∙K⁻¹)	0.52
入口水温度/K	308.15
管内流体导热系数/(W·m⁻¹∙K⁻¹)	0.6
岩体初始温度/K	291.15
岩体孔隙率/%	1
岩体渗透率/m²	1×10⁻¹⁵^[18]
裂隙水流速/(mm·s⁻¹)	1^[19]
U型管管内流速/(m·s⁻¹)	1.2
制冷周期/月	24
U型管管道长度/m	135
岩体导热系数/(W·m⁻¹∙K⁻¹)	3
岩石比热容/(J·kg⁻¹·K⁻¹)	800

下载: 导出CSV

表 2 热响应测试数据

Table 2 Thermal response test data

指标	数值
岩体平均原始地温/K	290.95
供水温度/K	291.15
流速/(m·s^–1)	0.8
U型管深度/m	150
U型管内/外径/mm	26/32
U型管管间距/mm	80
运行时间/h	48
岩体导热系数/(W·m^–1∙K^–1)	2.85
回填材料导热系数/(W·m^–1∙K^–1)	2.2

下载: 导出CSV

表 3 地埋管群出口水温

Table 3 Outlet water temperature of buried pipe group

时间/月	温度/K
时间/月	PK	MK	FK	NK
1.5	300.41	300.10	300.97	301.69
2.0	300.89	300.75	301.23	302.18
2.5	301.36	301.17	301.46	302.44
3.0	300.54	301.45	301.62	302.71
3.5	299.28	301.74	301.35	302.97
4.0	298.02	302.02	301.15	303.18
4.5	296.76	301.78	299.03	301.68
13.5	300.03	302.11	301.81	303.13
14.0	301.65	302.37	302.04	303.53
14.5	302.02	302.62	302.18	303.78
15.0	302.32	302.88	302.33	304.02
15.5	302.63	303.13	302.47	304.17
16.0	302.93	301.91	302.30	304.31
16.5	302.29	300.29	300.89	303.59

下载: 导出CSV

表 4 热泵机组制冷系数COP

Table 4 Unit performance coefficient COP

时间/月	制冷系数COP
时间/月	PK	MK	FK	NK
1.5	7.5	7.5	7.4	7.3
2.0	7.4	7.4	7.4	7.3
2.5	7.4	7.4	7.4	7.2
3.0	7.5	7.4	7.3	7.2
3.5	7.6	7.3	7.4	7.2
4.0	7.8	7.3	7.4	7.2
4.5	7.9	7.3	7.7	7.3
13.5	7.5	7.3	7.3	7.2
14.0	7.3	7.3	7.3	7.1
14.5	7.3	7.2	7.3	7.1
15.0	7.3	7.2	7.3	7.1
15.5	7.2	7.2	7.2	7.0
16.0	7.2	7.3	7.3	7.0
16.5	7.3	7.5	7.4	7.1

下载: 导出CSV

表 5 单位井深换热量

Table 5 Heat transfer per well depth

时间/月	单位井深换热量/(W·m⁻¹)
时间/月	PK	MK	FK	NK
1.5	100	104	93	83
2.0	94	95	89	77
2.5	88	90	86	74
3.0	98	86	84	70
3.5	114	83	88	67
4.0	131	79	90	64
4.5	147	82	118	83
13.5	105	78	82	65
14.0	84	75	79	60
14.5	79	71	77	56
15.0	75	68	75	53
15.5	71	65	73	51
16.0	67	81	75	50
16.5	76	101	94	59

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