Rollback Law of Reverse Smoke Flow in a Horizontal Airway during Mine Fire

Rollback smoke is one kind of familiar turbulent flow during mine fire and may cause serious damage and injury. The rollback law of reversal smoke flow is significant to mine fire rescue. The theories of environmental fluid mechanics and heat transfer are applied to study on the rollback law of the reversal smoke flow in a horizontal airway during mine fire. The heat transfer process between the reversal smoke and the airway wall is analyzed. Through the analysis above, the rollback distance equation of the reversal smoke is formed. The mass flux of the reversal smoke flow at the reverse point above the fire source and under the roof and the temperature at the point before smoke reverse again are the key points of working out the equation. At the stagnation before smoke reverse again, namely at the stagnant point of the reversal smoke, the pressure between smoke flow and airflow is equal and thus a pressure equilibrium equation is built up. Combined with the smoke plume model and gas state equation, the mass flux of the reversal smoke and the temperature at the stagnant point are worked out. At a result, the function of rollback distance of the reversal smoke is educed and simplified in order to be used in practice.