In the process of medium-deep geothermal development, the vertical anisotropy of the formation is often ignored. In order to study the influence of different factors on the heat transfer performance of the medium-deep casing geothermal buried pipe under various strata, the geothermal gradient and thermal conductivity of different strata in Guanzhong Basin were determined. The numerical heat transfer model of the medium-deep casing geothermal buried pipe based on the multi-parameter vertical stratification of the strata was established by COMSOL numerical calculation software. Firstly, the difference between the two heat transfer effects of stratification and homogeneity was compared and analyzed. Then, the effects of factors such as circulating flow rate, inlet water temperature and thermal conductivity of the inner tube on the heat transfer performance of the casing heat exchanger were simulated. The results show that when the heating season (120 d) is continuously operated, the heat taken per unit time of the layered model is 49.03 kW higher than that of the homogeneous model, and the layered model can better reflect the stratification of the ground temperature recovery speed caused by the formation difference. The outlet water temperature decreases with the increase of the thermal conductivity of the inner tube, and the heat intake also decreases. Increasing the circulating flow rate can increase the heat taken per unit time, but when it is greater than 25 m3/h, the growth rate gradually slows down. The study can provide reference for the development and utilization of deep geothermal in Guanzhong Basin.
SHEN Hao, LI Yong-qiang, WANG Qi-long, ZHAO Yong-zhe.
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Science Technology and Engineering, 2026, 26(10): 4048-4054 DOI:10.12404/j.issn.1671-1815.2502709
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