唐晓音，程璐瑶等——西安地区中深层套管式地埋管换热性能数值模拟

（1. 中国地质科学院地质力学研究所 北京 100081；2. 西安交通大学，人居环境与建筑工程学院 西安 710049；3. 中国地质调查局西安地质调查中心 西安 710054；4. 信息产业部电子综合勘察研究院 西安 710054）

摘　要　本文建立了符合西安地区地热地质的三维地质模型，基于FEFLOW软件模拟了入口流量、入口温度、换热井深度以及出水管管材导热系数4种参数对套管式地埋管换热器换热性能的影响，以换热量为换热性能衡量标准，探究如何合理设置参数来提高换热效率。结果表明：1）增加入口流量会导致出口端温升降低、换热量增大，西安地区入口流量设置在15~25 m3/h最为适宜；2）增加换热井深度会使得出口端温升和换热量呈指数增长，井深对换热量的影响主要取决于换热段所处地层温度及换热时长，岩石导热系数贡献较小；3）针对西安地区，入口温度对换热量的影响最为明显，出水管管材导热系数和换热井深度次之，入口流量影响效应相对较弱。本研究对西安地区中深层地埋管换热系统设计施工和地热能勘探开发具有指导和参考意义。

Numerical study on factors that influence the heat transfer performance of mid-deep coaxial casing heat exchanger in the Xi’an area

Abstract：In order to find optimal parameters to promote the heat transfer rate for the coaxial casing heat exchanger in the Xi’an area, we established a three-dimensional geological model in this study, and then simulated the influence of four parameters, that is the inlet water flow rate, inlet water temperature, heat exchange borehole depth, and the outlet inner pipe thermal conductivity, on the heat transfer performance. The results show that: 1) Increasing the inlet water flow rate will lead to an increase in heat exchange, but a decrease in outlet water temperature. It is most appropriate to set the inlet flow rate at 15 m3/h ~25 m3/h in Xi’an area; 2) Increasing the depth of the heat exchange borehole will cause exponential growth in outlet water temperature and the heat transfer. The influence of borehole depth on the heat transfer mainly depends on the formation temperature and heat transfer duration rather than the thermal conductivity; 3) For the Xi’an area, the inlet water temperature has the most obvious impact on the heat transfer, followed by the thermal conductivity of the outlet pipe, the depth of the heat exchange borehole and the inlet water flow rate. This study is not only significant for the design and construction of the buried pipe heat exchange system, but also for the exploration and development of geothermal energy in Xi’an area.

Keywords　Xi’an area, Coaxial casing heat exchanger, Effect factors for heat transfer, Numerical modeling

doi:10.12017/dzkx.2021.051

1　关中盆地地质单元图（据柯婷婷等, 2019修改）

Fig. 1　Schematic geological map of the Guanzhong  Basin (modified from Ke et al., 2019)

2　数值模拟西安地区三维地质模型

Fig. 2　3D geological model of Xi'an area for numerical simulation

https://blog.sciencenet.cn/blog-400480-1295830.html

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