Study on the influence of air volume on roof fire in the middle of single heading roadway

Abstract

In order to study the influence of local fan air volume on personnel disaster avoidance in the early stage of roof fire in the middle of single heading roadway, PyroSim software was used to analyze the distribution of smoke flow, temperature, CO concentration and visibility in the roadway under seven working conditions of 450 m3/min, 675 m3/min, 900 m3/min, 1 125 m3/min, 1 350 m3/min, 1 575 m3/min and 1 800 m3/min. The results show that the roof fire smoke flows directly to both ends along the roof, with no rising plume phenomenon, when the air volume is lower than the critical wind speed, the backflow length and smoke flow thickness gradually decrease with the increase of ventilation air volume. When the roof fire is stable and there is smoke backflow, along the longitudinal direction, the peak values of CO concentration and visibility are in a certain area behind the smoke front, while the peak value of temperature is below the fire source, and there is a high temperature zone and environmental temperature zone in the upwind direction of the fire source, while the smoke density, temperature, CO concentration and visibility in the exit direction are relatively stable; under the fire source, the temperature increases with the increase of height, while the visibility decreases; with the increase of wind volume, the peak values of temperature at 2 m gradually decrease, the minimum visibility in the roadway gradually increase, while the CO concentration first increases and then decreases, and the peak positions of the three parameters move towards the outlet. From the perspective of personnel escape, it is concluded that the greater theventilation is, the more conducive to escape, and 1 350 m3/min can meet the escape conditions.

Keywords

• local ventilation
• air volume
• single heading roadway
• roof fire
• numerical simulation
• disaster avoidance