The combined effects of methane draft pressure and heat wind pressure on airflow behavior in parallel roadways: a simulation study

Abstract

ABSTRACT When a large amount of methane accumulates in a high-temperature tilted roadway in deep wells, methane draft pressure (MDP) and heat wind pressure (HWP) are generated simultaneously. The combined effects of MDP and HWP influence the stability of the airflow in wells and threaten mine safety. In this study, a joint model related to the airflow temperature and the methane concentration in each branch is developed. According to the developed model, a new unsteady ventilation network calculation program is established using the Visual C++ programming language based on the original unsteady ventilation network calculation program. In addition, experiments are conducted to verify the reliability of the program. A detailed comparison of the simulation and the experimental parameters (i.e. wind speed, methane concentration, and airflow temperature) indicates that although certain values deviate, a notable correlation exists between the simulation and the experiment. The improved program is used to investigate the combined influences of MDP and HWP on the airflow stability of the parallel branches in the event of different elevations in downward ventilation. As the temperature of the methane containing branch increases from 15 °C to 45 °C, airflow stagnation gradually occurs in the main branch at a height difference of 3 m, and the airflow behavior changes from airflow stagnation to airflow circulation at a height difference of 100 m. The simulation results indicate that the influence of the airflow temperature on the airflow behavior varies with the height difference in the downward-ventilated roadways. Furthermore, the airflow behavior becomes more complex as the airflow temperature increases.