An investigation on spill plume temperature of large space building fires

Abstract

In fire safety engineering, rapid fire detection and suppression in large spaces are very important issue. Development of new techniques is always based on the good understanding of the basic principle of smoke movement, especially the temperature of spill plume. Aiming to this objective, this paper specifies the multi-sectional characteristics on spill plume free developing out of a wide-door cabin in a large space atrium by means of full-scale experiment, theoretical analysis and CFD modeling. First the physical development process of the spill plume is analyzed from the horizontal curved regime at the door, the near-field two-dimensional linear plume regime, through to the far-field axisymmetric plume regime. It demonstrates the coupling correlation existing between the linear virtual origin, critical transition height from linear to axisymmetric regime, the axisymmetric virtual origin and other parameters, such as the spill plume depth at the door, the mass and heat flow rate outside the cabin door, the cabin door width and height etc. The basic mathematic equations regarding each regime's centerline temperature have been obtained. The virtual origin position of linear plume regime and axisymmetric plume regime are given, the critical transition height of spill plume from the two-dimensional linear plume to axisymmetric plume regime is also proposed, and finally the double-part prediction model (MEDP) for the spill plume centerline temperature is put forward. By validation with the full-scale experiment and the large eddy CFD modeling, it shows that the proposed spill plume model is capable to well describe the centerline temperature varying characteristics of the spill plume free developing out of the cabin.