NUMERICAL MODELLING OF ATRIUM FIRES

Abstract

In this dissertation, a fire field model based on the Computational Fluid Dynamics (CFD) is used to study the temperature and velocity profiles in different shapes of atriums. A computational procedure for predicting velocity and temperature distribution in fire-induced flow is based on the solution of three-dimensional Navier-Stokes conservation equations for mass, momentum, energy, etc. using a finite volume method and non-staggered grid system. Since air is entrained from the bottom of the plume, total mass flow in the plume continuously increases. Also, the ceiling jet continuously decreases in temperature. The field model is proposed to substitute the zone model (CFAST) for predicting the smoke layer temperature and because zone models assume that a stable and homogeneous smoke layer is formed, even in a large atrium spaces. The temperature profiles obtained through fire field model are matching with zone model with little variation and field model results are acceptable as it is more accurate. Cylindrical shaped atrium having conical dome was found to be the appropriate shape. Temperature was found to be lower at the same location in this type of atrium when compared to other atrium having different types of domes and dimensions.