Computational Investigation of Shearer Movement and Drum Rotation Effects on Airflow and Methane Dispersion in Longwalls Using Integrated Dynamic and Overset Meshing

The movement of mining equipment complicates predicting and managing methane dispersion, with the dynamic interaction between machinery and gas flows significantly impacting methane concentrations and safety. This computational study investigates the impact of shearer operation on airflow, methane and oxygen dispersions in longwall mining using advanced transient computational fluid dynamics (CFD) simulations. For this purpose, dynamic and overset meshing techniques are innovatively integrated to model both translational (0.5 m/s) and rotational (60RPM) shearer movements, providing an advanced approach to improving accuracy while reducing computational costs in dynamic scenarios. To capture the intricate interactions between the moving shearer and methane dispersion, the computational domain is also divided into five sub-zones. The dynamic model's performance is validated using existing experimental data. Additionally, unlike earlier studies that simplified methane flow from mining face as uniform, our research presents a more realistic scenario where methane concentration peaks in front of the moving shearer and dynamically shifts along the mining face as the shearer progresses. The results indicate that the shearer's movement and counter-rotating cutting drums create significant turbulence, altering airflow that can substantially affect the dispersion of gas around the cutting face and tailgate. The average gas flow velocity at the tailgate after 80 s increases from 3.59 (non-operating condition) to approximately 5.78 m/s as the shearer advances, while average methane concentration at the tailgate reaches 2.4 %. The findings of this research contribute significantly to improving mining safety and ventilation design, particularly through the improvement of real-time methane measurement under dynamic conditions in underground mining.