Study on numerical simulation of variations of airflow field and gasconcentration during roadway fire

This paper aims to properly control the inlet air velocity of roadway and reduce the occurrence of fire and its damage in coal mines. Fluent is used to conduct the numerical simulation of airflow in a coal mine roadway in the presence of fire. The effects of different inlet speeds on the velocity field, temperature field and distribution of gas emission are discussed. The results show that the greater inlet air velocity is associated with smaller influence on air flow distribution in the roadway and the lowest air velocity is located in the flame zone.The longitudinal distribution profile of the velocity forms an “arc layered” shape.As fire increases the gas concentration in the roadway, when air velocity is low, the gas concentration can reach the lower limit of gas explosion,causing gas explosion. Changes of air velocity would cause large change in the distance of “smoke flow back”. The greater the air velocity is, the more significant the smoke exhaust effect in the roadway is. The simulation results show that properly control of the inlet air velocity of roadways has a significant effect on preventing gas explosion and smoke emission in the roadway after fire and explosion.