Spray atomization characteristics are presented for an industrial diesel fuel oil and a 2 MW, 60° pressure-swirl atomizer, operating over a pressure range from 7 to 15 bar. These characteristics are compared with results achieved using the same nozzle with water as the atomized fluid. The results achieved for the fuel oil have been based upon a phase Doppler anemometry (PDA) investigation during which three scattered light collection angles (68°, 150° and 110°) were employed, with 110° scattering perpendicular polarized laser light was used, whereas parallel polarization was employed for the other two scattering angles. Significant variations in both the individual droplet histograms and the Sauter mean diameters have been observed.
For this presentation the comparison will be based on the use of the same two-dimensional PDA transmission optical geometry and a 4 W argon-ion laser. The scattering angle of 68° represents the Brewster angle for the fuel oil. This presentation therefore provides a detailed comparison between the results achieved using the Brewster angle (72°) for water and demonstrates the influence of liquid viscosity, surface tension and density upon the spray field characteristics.
The structure of the fuel spray was such that the measurements could only be achieved over the region close to the nozzle, so the comparison is restricted accordingly. The measured variation of Sauter mean diameter (Dn) is also compared with the results achieved from the empirical correlations of Radcliffe and Jasuja for both fluids considered.