Numerical Simulation of Critical Velocity in Ventilation

Abstract

Given the importance of the safety and health of passenger’s in underground tunnels, analysis and simulation of fires in tunnels is to design a ventilation system. Longitudinal ventilation systems are widely used in tunnel ventilation and are one of the most important parameters for fire safety in this type of critical velocity system. Critical velocity of ventilation is minimum longitudinal velocity flow of air that prevents the smoke from the fire to the upstream flow.In this study, the effects of the distance between the fire source of the tunnel, obstacle before and after the fire, several sources of fire in the tunnel and ventilation shaft tunnels will be discussed on the critical velocity. Each effect parameter according to a correlation analysis of numerical results obtained using the solver FLUENT software Airpak and then the relationship between dimensionless critical velocity and dimensionless heat release are stated.