Research On Flame Characteristics Ejected From Opening Of A Confined Space

Abstract:The phenomenon of fire spread through the opening of building to the outside surface calls opening fire ejecting phenomenon. Combustion characteristics of confined space opening fire ejecting not only affected by their thermal buoyancy and wind outdoor environment, but also by the spatial structure of the layout of the fire, the opening size and distribution of fire load etc. The influence of different opening sizes on the combustion characteristics of opening fire ejecting phenomenon is studied using theoretical analysis and numerical simulation methods for fixed fire load on this paper based on previous studies. The main contents of this paper are as follows:(1) On the basis of the mechanism of opening fire ejecting phenomenon analysis, the concept of confined space participation rate of air flowing into the combustion is introduced in, and based on this the calculation method of fire heat release rate of the confined space and the outdoor is established.(2) Based on the single area of confined space simplified model, the fire burning characteristics of confined space is analyzed. And the change rule of the inflow rate of air quality of confined space, the fire heat release rate of the confined space, the participation rate of air flowing into the combustion, the average temperature rise of the confined space and other characteristic parameters with the opening size is obtained.(3) Combined with the change rule of neutral plane height, flow rate, temperature and other parameters of the confined space surface opening positions, mechanism of exterior wall adherent effect and spill plume combustion characteristics are analyzed based on large space near the wall model. And the radial temperature distribution of the exterior wall and the plume center trajectory curve change rule with the opening size are obtained.Researches on plume mostly concentrated on the axisymmetric plume of large space, the change rule of the combustion characteristics of opening fire ejecting phenomenon with opening sizes is studied using theoretical analysis and numerical simulation methods for fixed fire load in this paper, and provide reference for the research on building facades vertical fire spread.