Abstract
Methane draft pressure is a secondary disaster for mine ventilation following coal and gas outbursts, which poses a long-term threat to coal mining and workers’ safety. To study the law of methane draft pressure-caused airflow variation, oscillation theory is introduced in this study. The vibration equation is used to deduct the basic equation of airflow oscillation in parallel upward ventilated airways, which regards the entire methane and air as one vibrating object in the loop of the parallel airways. The theoretical critical air velocity to prevent airflow reversion is calculated by the airflow oscillation equation using numerical methods. Furthermore, through dimensional analysis, a formula is given to calculate the critical velocity directly. The theoretical results were compared with experiments and good agreements were obtained, which verifies the rationality of the assumptions in the theoretical deduction process. The conclusion of this study indicates that, in a short time, oscillation theory can be used to predict the critical air velocity to prevent airflow reversion, and be feasible in revealing the essence of methane draft pressure-caused airflow reversion.
HIGHLIGHTS
An airflow oscillation model is built to analyze and predict methane draft pressure-caused airflow reversion based on oscillation theory.
A method is carried out to calculate the critical velocity that prevents airflow reversion based on the airflow oscillation model.
The conclusions of this paper provide a theoretical basis for further understanding the essence of the airflow reversion caused by methane draft pressure.
Disclosure statement
No potential conflict of interest was reported by the author(s).
Additional information
Funding
Notes on contributors
Zeqi Wu
Zeqi Wu received his Ph.D. degree of safety science and engineering from China University of Mining and Technology, Beijing. He is a lecturer who is currently working at school of Building Environment Engineering, Zhengzhou University of Light Industry. His area of research include mine ventilation, mine gas prevention and control, and fire smoke control.
Kai Wang
Kai Wang is a professor who is currently working at College of Emergency Management & Safety Engineering, China University of Mining and Technology, Beijing. He majors in mine ventilation and safety, gas outburst and coal mine safety.
Huaitao Song
Huaitao Song is a lecturer who is currently working at school of Building Environment Engineering, Zhengzhou University of Light Industry. He majors in mine ventilation and thermal hazards in mines.
Kun Wang
Kun Wang is currently working toward the M.S. degree in electrical engineering with the school of Building Environment Engineering, Zhengzhou University of Light Industry. His research interests include coal mine safety and fire smoke control.
Lin Shao
Lin Shao is an experimentalist who is currently working at school of Building Environment Engineering, Zhengzhou University of Light Industry. Her majors in coal mine safety.