The Airflow Reversal Law in Ventilation System after Coal and Gas Outburst in Tunneling Roadway

Table 1

Boundary conditions.

Boundary category	Location	Boundary type	Species	Gauge total pressure
Inlet boundary	Inlet of return airway	Pressure inlet	O2 = 20%, N2 = 80%	6 Pa
	Outburst	Pressure inlet	CH4 = 100%	(1, 5, 10, 50,100, 500) hPa; (0.1, 0.4, 0.64, 0.9, 4.9) MPa
Outlet boundary	Air duct outlet	Velocity inlet	O2 = 20%, N2 = 80%	−14 Pa
	Outlet of return airway	Pressure outlet