DROPLET SIZE AND VELOCITY CORRELATIONS FOR A COAXIAL AIR BLAST ATOMIZED JET

The structure of a coaxial, airblast atomized water jet is interrogated under sea-level pressure-temperature conditions. Detailed measurements of droplet size and velocity are carried out over a wide range of atomizing air velocity at two axial planes using single-component Phase Doppler Anemometry. Mean drop size, velocity and spatial homogeneity are found, as expected, to be a function of atomizing air velocity and probing plane axial distance. Aerodynamic Weber number analysis reveals the disintegration process in the near-field inner region to be incomplete whilst the droplet Reynolds numbers in the far-field region approach that of the original liquid jet. Mean drop size - mean drop velocity correlation shows distinctly different slopes for the near and far-field regions which may reflect the different atomizing time history.