https://orcid.org/0000-0002-4298-0380
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ABSTRACT
With the increasing number of high-temperature mines, there has been a growing focus on research into thermal environment management and prediction in long-distance ventilation roadways. Mastering the principles of heat transfer in roadways is crucial for enhancing ventilation performance and achieving energy savings in mine heat hazard control. A one-dimensional ventilation ultra-long roadway with high precision and low weight is presented in this study, which accurately depicts the dynamic heat transfer between the airflow and three-dimensional surrounding rock (SR) of roadway. The calculation time of the one-dimensional roadway numerical model is reduced by over 90%. The accuracy of the proposed numerical model is verified by the heat convection within roadway wall and the heat transfer in SR. In addition, the evolution of the temperature field and Nusselt (Nu) number of ultra-long roadway wall regarding ventilation time and periodic fluctuation of initial temperature of airflow (TA) are analyzed. The results indicate that the temperature of SR and Nu number of ultra-long roadway wall both periodic changes with the fluctuation of TA, and the TA and Nu number of ultra-long roadway wall fluctuate in opposite phases. When the TA temperature ranges from 15 to 25°C, the Nu number of ultra-long roadway wall changes in the range 90 in a year. The Nu number of ultra-long roadway wall decreases with the increase of ventilation distance. Additionally, the TA in ultra-long roadway exhibits a linear relationship with both the initial TA, the thermal conductivity of SR, and the initial temperature of SR, but it is subject to negative exponential decay in relation to ventilation speed. As the length of the roadway increases, fluctuations in the initial TA have less impact on the thermal environment within the long-distance ventilation roadway, while ventilation speed, thermal conductivity of SR, and initial temperature of SR become more influential factors.
Disclosure statement
No potential conflict of interest was reported by the author(s).
Nomenclature
| A | = | Cross-sectional area of the roadway/m2 |
| Cp | = | Specific heat capacity/J·(kg·K)−1 |
| dh | = | Mean hydraulic diameter/m |
| e | = | Surface roughness of roadway/m |
| fD | = | Darcy friction factor |
| g | = | Gravity acceleration/m·s−2 |
| h | = | Heat transfer coefficients/W·(m2·K)−1 |
| k | = | Thermal conductivity of airflow/W·(m2·K)−1 |
| K | = | Thermal conductivity/W·(m2·K)−1 |
| Kw | = | Thermal conductivity of the linking/W·(m·K)−1 |
| l | = | Characteristic length (m) |
| Nu | = | Nusselt |
| p | = | Gas pressure/Pa |
| Pr | = | Prandtl number |
| Q0 | = | Heat source in rock/W·m−3 |
| Qm | = | Heat source inside the roadway/W·m−3 |
| Qwall | = | Convective heat transfer on roadway wall/W·m−1 |
| Qp | = | Self-compression heat release/W·m−3 |
| Re | = | Reynolds number |
| SR | = | Surrounding Rock |
| t | = | Time/s |
| T | = | Temperature/K |
| TA | = | Temperature of airflow/K |
| u | = | Averaged velocity in cross-sectional of roadway/m·s−1 |
| Z | = | Circumference of the roadway/m |
| Greek symbols | = | |
| ρ | = | Density/kg·m−3 |
| θ | = | Porosity |
| αp | = | Thermal expansion coefficient/K−1 |
| φ | = | Initial phase of the periodic change function |
| Subscripts | = | |
| a | = | Air |
| ins | = | Inside of the one-dimensional roadway |
| ext | = | External of the one-dimensional roadway |
Additional information
Funding
Notes on contributors
Gang Li
Gang Li, professor and doctoral tutor of State Key Laboratory of Safety and Health for Metal Mines. His research interests are centered on the occupational health and safety.
Yu Xu
Yu Xu, Lecturer of Central South University. His research interests are centered on the areas of safety science and engineering, heat hazard control, and geothermal resource utilization.
Zijun Li
Zijun Li, professor and doctoral tutor of Central South University. His research interests are centered on the areas of safety science and engineering, fire prevention theory and technology.
Yin Chen
Yin Chen, candidate at Central South University. He is currently the General Manager of Xinjiang Kalatongke Mining Co. LTD. His research interests include ventilation and safety management.
Xiaowei Zhai
Xiaowei Zhai, professor and doctoral tutor of Xi’an University of Science and Technology. His research interests are centered on the areas of fire prevention theory and technology.
Rongrong Li
Rongrong Li, candidate at Central South University. Her research interests include mine ventilation and occupational health.
Kaiqi Zhong
Kaiqi Zhong, candidate at Central South University. Her research interests include heat hazard control and geothermal resource utilization.