Numerical study on the effect of blower location on the maximum temperature and spread of smoke in case of fire inside tunnels

Designing of an efficient emergency ventilation system is one of the main approaches to prevent the perilous fire in tunnel phenomenon.One of the most considerable factors in smoke control is critical velocity.In the present work, a parameter is called a critical volume flux, which indicates at least a volumetric flow that prevents smoke from flowing upstream of the fire. In this study, fire in tunnel is simulated using Fire Dynamics Simulator code (FDS) and The effect of blower location on maximum temperature, spread of smoke and critical volume flux of fire in the tunnel has been investigated. The results show that the blower location has a significant effect on critical velocity and volumetric flux and it can reduce critical volumetric flux by at least 11 percent . Also, for a closer look by creating a variety of conditions in the blower system, the effect of fire source height has been investigated on the critical volume flux. The results also show that increasing the fire source's height does not have a significant effect on volumetric flux and critical velocity. In the study of longitudinal distance of the blower system from the fire source, in the case of back-layering smoke, the results show that the approach of the blower to the fire would reduce the smoke back-layering length and increase the maximum temperature.