Numerical study on heat transfer between airflow and surrounding rock with two major ventilation models in deep coal min
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ORIGINAL PAPER
Numerical study on heat transfer between airflow and surrounding rock with two major ventilation models in deep coal mine Pingye Guo 1,2 & Yi Su 1,2 & Dongyang Pang 1,2 & Yanwei Wang 3 & Zhibiao Guo 1,2 Received: 22 August 2019 / Accepted: 10 July 2020 # The Author(s) 2020
Abstract Not only is the thermal environment of the coal mining face related to the temperature of the surrounding rock, it is also closely associated with the ventilation model of the working face. In this study, the numerical methods were applied to study the impact of two major ventilation systems on the airflow temperature of working face in coalmine. Firstly, a heat transfer model of the surrounding rock and airflow was established to reveal that the wall roughness of the surrounding rock could enhance heat transfer between the surrounding rock and the airflow. Moreover, an analysis was conducted of the heat transfer between the airflow and the surrounding rock under different modes of ventilation in the first mining face. According to the analytical results, the temperature of airflow in the U-type ventilation system is lower than in the Y-type ventilation system. For the next adjacent coal mining face, however, the Y-type ventilation system is more conducive in reducing the temperature of the airflow. Therefore, with regard to the mine as a whole, the Y-type ventilation system is more effective than a U-type system in reducing heat and humidity in the ambient environment. Keywords Ventilation . Heat transfer . Deep mine . Hot and humidity environment
Nomenclature T Temperature, °C Q Heat, W k Thermal conductivity, W/(m2·°C) v Velocity, m/s h Heat transfer coefficient, W/(m2·°C) p Pressure, Pa t Time, s Greek symbols α Thermal diffusivity, m2/s ρ Density, kg/m3 μ Viscosity, Pa·s Responsible Editor: Zeynal Abiddin Erguler * Pingye Guo [email protected] 1
State Key Laboratory for Geomechanics and Deep Underground Engineering, Beijing 100083, China
2
School of Mechanics and Civil Engineering, China University of Mining and Technology, Beijing 100083, China
3
China Institute of Water Resources and Hydropower Research, Beijing 100038, China
Subscripts r rock f airflow
Introduction There are plenty of mine operations conducted in an environment with intense heat and high humidity, due to the high ground temperature. Particularly, in many deep mines, it is necessary to apply the mine cooling system for reducing the high levels of temperature and humidity in the surrounding environment (Sasmito et al. 2015; Guo et al. 2017; Feng et al. 2018). As for the airflow in mine, the most significant source of heat is the surrounding rock, with the fresh rock surface on the working face in particular (Zhang et al. 2017; Maurya et al. 2015). In order to design an optimal mine cooling system, it is essential to understand not only the heat transfer law between the surrounding rock and the airflow in mine but also how the airflow temperature field is distributed (Lu et al. 2017; Wang et al. 2018a, b). Up to now, there are plenty of
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