Transverse and lateral temperature profiles of the window-ejected thermal plume along the facade

Abstract

The window-ejected thermal plume along the building facade is one of the most classical scientific problems of building fire dynamics, which is an important transition of the fire from the inside of the compartment to the building facade. The present study investigates the temperature profiles and evolutions of the window-ejected thermal plume by experimental and theoretical analysis. The experiments were conducted using a reduced-scale cubic compartment and a facade. Three-dimensional (transverse/lateral/vertical) temperature fields are measured and quantified by the thermocouple array considering various heat release rates, window dimensions and its aspect ratios. It is found that: (1) the vertical temperature along the center line of facade first increases then changes a little at the flame region, decreases at the plume region. (2) The transverse or lateral temperature decreases more significantly at the flame region than the plume region. (3) For the flame region, the temperature first changes a little or decreases slightly with increasing transverse distance, however, for the plume region, the temperature first increases, then decreases with increasing transverse distance. A physical model of the window-ejected thermal plume considering the flame and plume regions including characteristic length scales is proposed to describe the transverse and lateral temperature profiles, in which the window characteristic length, effective characteristic width/thickness and the height above the neutral plane are considered in general to reflect temperature profile. The present study provides new observations, experimental data and theoretical analysis of the window-ejected thermal plume temperature profile, which is beneficial for the building facade fire-proof design.