Spray Atomization and Links to Flame Stability over a Range of Weber Numbers and Pressure Ratios

Abstract

This paper presents an assessment of flame stability and spray characteristics over a wide range of Weber numbers and dynamic pressure ratios (or momentum flux ratios) using the Sydney needle burner (SYNSBURN) which employs air-blast atomization. Several fuels and needle sizes are used to study flows spanning equivalence ratios of 0.6 to 3.2, Weber numbers of 150 to 1050, and dynamic pressure ratios of 0.3 to 9.06. It is found that peak flame stability occurs at an optimal equivalence ratio, which is dependent on the Weber number and hence the quality of the spray. This strong correlation between flame stability and spray quality inspired further analysis on a description of the atomization process using nondimensional numbers. The breakup length and atomization rate are studied by analyzing the decay in normalized spray volume or area measured using high-speed multiangle microscopic imaging. It is found that the dynamic pressure ratio is a more dominant parameter than Weber number in terms of predicting the breakup length, while both parameters are relevant to downstream droplet size. The paper also presents correlations between the atomization parameters and relevant nondimensional numbers.

Virtual Special Issue of Recent Advances in Fundamentals of Biomass and Biofuel Combustion

“…16 The last paper in this group described spray vaporization characteristics of alcohols and esters. Specifically, Singh et al 17…”

“…Lokachari et al 14 16 The last paper in this group described spray vaporization characteristics of alcohols and esters. Specifically, Singh et al 17 investigated acetone, ethanol, and biodiesel spray flames to link the spray characteristics and flame stability.…”

Statistics and dynamics of a liquid jet under fragmentation by a gas jet

“…By increasing the gas velocity at several values of the liquid Reynolds number (liquid velocity), the explored parameter space crosses this transition many times at various values of M, giving the possibility to uncouple We g (change of regimes) and M (scalings of L B ). An alternate approach would be to vary the parameters of the fluids (in particular the fluids densities and the surface tension coefficient) [21,26,27], which is more challenging in the current setup. In the approach where only the liquid and gas velocities are varied, the effects of the gas velocity are equivalently described by We g and Re g .…”