Facade flame height ejected from window of a compartment fire under a single sidewall constraint boundary condition

Abstract

Under the boundary condition of single sidewall constraint, this study investigates the relationship between the window dimension, heat release rate, and sidewall distance and the development law of the mean flame height. Based on the characteristic length scale of the window of the combustion chamber l1=(AH)2/5 as the dividing point, the mean flame height variation law with sidewall distance D is revealed to be as follows: for l1<D, as the distance between the sidewalls increased, the mean flame height did not change significantly; for l1/2≤D ≤ l1, a decrease in the distance between the sidewalls increased the mean flame height. A flame entrainment model under sidewall constraint boundary conditions was developed based on the evolution law of mean flame height and flame entrainment characteristics of the window to describe the difference in mean flame height between the free boundary without a sidewall. Furthermore, the limit boundary of a sidewall, the mean flame height correction factor K was introduced. The non-dimensional mathematical expression of the mean flame height under a single sidewall constraint boundary condition was established and verified.

Keywords

• Compartment fire
• Single sidewall
• Thermal ejected plume
• Flame entrainment
• Mean flame height