The effect of pressure on the characteristics of laminar jet diffusion flame: A similarity analysis and experimental study

Abstract

Although the effect of pressure on the characteristics of laminar diffusion flame has been extensively studied, there is need of simple similarity correlations for flame shape and radiation fraction, which can be useful for application to turbulent flows and fire safety. In this paper, similarity analysis for flow and soot models is developed, where non-dimensional parameters were defined for the flame geometry and the radiation fraction. For validation, small ethanol pool fires with diameter of 1.5 cm were conducted in a pressure chamber at different pressures ranging from 1 to 5 atm, where the flame shape and radiation fraction were measured. Results show the characteristic lengths of the flame geometry including flame height, flame width, flame oscillation length, flame frequency and flame volume could be well correlated using the non-dimensional similarity parameter. Furthermore, the globle relationship for non-dimensional radiation fraction was verifed based on measured value in current and previous study, where the non-dimension radiation fraction could be well correlated by the −0.30 power of Sṁfμν2g13. Comparison with literature experiments are also presented and discusssed.