Study on the mechanism of gas wind pressure induced wind flow oscillation after outburst disaster

The wind flow oscillation effect is an important characteristic of the post-disaster mine ventilation network, but there are few studies on the wind flow oscillation phenomenon and there is a lack of in-depth discussion on the wind flow oscillation characteristics. In order to solve the above problems, taking the parallel downward ventilation network as the research object, the oscillation effects of disaster wind flow and gas mass are studied.Based on the damped vibration theory, an open-loop airflow oscillation model is constructed and the Runge-Kuttamethod is used to solve the numerical problem in Matlab software so as to analyze the oscillation characteristics of the gas mass in the parallel roadway. As the initial wind speed increases, the amplitude of the gas mass increases and the impact range of gas in the parallel pipeline is expanded.A similar model of the actual roadway is established to simulate the change of wind speed in parallel roadways with time. The experimental results show that due to the effect of gas wind pressure and ventilator wind pressure, the wind speed repeatedly increases and decreases in the parallel roadways, i.e. wind flow oscillation phenomenon. When the initial wind speed increases from 0.35 m/s to 0.62 m/s, the wind flow oscillation time is shortened from 50 s to 35 s, and the maximum reverse wind speed is changed from -0.4 m/s to -0.12 m/s. This shows that the increase of the initial wind speed is more conducive to the diffusion and discharge of gas mass.The prevention and control measures of wind flow oscillation in parallel inclined gas accumulation shaft are proposed, including imposing wind-blocking measures on the air branch; strengthening local ventilation and increasing wind speed on the gas branch.