Comprehensive understanding of the airflow temperature field in a high-temperature tunnel is critical for the deep underground engineering project. In this paper, we establish a two-dimensional axisymmetric model coupling the convective-conduction heat transfer based on the k - ε turbulence equation, by which the airflow temperature field in a high-temperature tunnel for geothermal mining is investigated. We compare the airflow temperature variation with or without thermal insulation layer (TIL) and introduce the valid ventilation distance (VVD) to quantify their differences. The sensitivity analysis of critical factors on the airflow temperature are also examined. We find that (1) the TIL has a remarkable insulation effect even in a high-temperature tunnel, and its insulation effect can be well quantified by the VVD; (2) the TIL insulation effect decreases dramatically as the rock temperature increases, resulting in an exponential decay in the VVD; (3) changing critical factors are effective for reducing the air temperature and increasing the VVD, but these impacts decrease rapidly as the rock temperature grows; (4) the established empirical formula facilitates the VVD estimation and favors parameter optimization in high-temperature tunnels of deep underground engineering projects.

全面了解高温隧道中的气流温度场对于深层地下工程项目至关重要。在本文中，我们建立了一个基于k-ε耦合对流传导热传导的二维轴对称模型。湍流方程，研究地热开采高温隧道中的气流温度场。我们比较有无保温层（TIL）时的气流温度变化，并引入有效通风距离（VVD）来量化它们之间的差异。还对气流温度的关键因素进行了敏感性分析。我们发现（1）TIL即使在高温隧道中也具有显着的绝缘效果，其绝缘效果可以通过VVD很好地量化；（2）随着岩石温度的升高，TIL的绝热效果急剧下降，导致VVD呈指数衰减；（3）改变关键因素对于降低空气温度和增加VVD是有效的，但是随着岩石温度的升高，这些影响迅速减小；