Turbulent spray flames of kerosene issuing from a hybrid electrohydrodynamic-air-blast atomiser

Abstract

This paper presents an experimental study of turbulent spray flames of kerosene atomised using a new hybrid air-blast/electrohydrodynamic atomiser. Electrohydrodynamic (EHD), or charge injection atomization applies to electrically insulating fuels where the liquid is a dielectric and does not require conductive additives. The study focuses on the influence of electric charge on the global stability and downstream flow-field and reaction zone structure of turbulent spray flames. Stability characteristics for the burner are examined with and without electric charge, and cover sprays over a broad range of aerodynamic Weber numbers, We. The velocity and droplet fields are measured using laser/phase Doppler anemometry, and results indicate a notable increase in particle concentration with the application of charge for both reacting and non-reacting sprays. With the addition of electric charge, it is found that the mean and rms velocity fields are not significantly influenced but a significant rise in particle concentration is noted and this is more pronounced for the lower We number cases. Planar laser induced fluorescence of OH shows clear influence of charge on the reaction zone structures pushing them to outer radial locations, whilst also reducing the intermittency in the area of OH fields over time. The burner provides a new experimental platform that enables the study of hybrid atomization as a means to modify spray and flame behaviour.