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Atomization and Sprays

Journal of the International Institutes for Liquid Atomization and Spray Systems

ISSN for PRINT: 1045-5110

Institutional price:	$787.00
Issues per year:	8

Best Paper Award Selection - Editorial Board Site

1999, Volume9

116 pages

Issue price - $75.00

DILUTE EMULSIONS AND THEIR EFFECT ON THE BREAKUP OF THE LIQUID SHEET PRODUCED BY FLAT-FAN SPRAY NOZZLES

M. C. Butler Ellis
Silsoe Research Institute, Wrest Park, Silsoe, Beds, United Kingdom

C. R. Tuck
Silsoe Research Institute, Wrest Park, Silsoe, Beds, United Kingdom

P. C. H. Miller
Silsoe Research Institute, Wrest Park, Silsoe, Bedfordshire, United Kingdom

ABSTRACT

Studies of the effect of dilute emulsions on spray formation by flat-fan nozzles have shown that the presence of emulsion particles changes the mechanism of liquid sheet breakup. Perforations in the liquid sheet occur at a position that is dependent on the nature and the concentration of the emulsified components. It has been suggested that perforations occur with particles of low wettability and when the liquid sheet thickness equals the particle diameter. We examined this by (1) investigating the relationship between the length of the liquid sheet and the diameter of the emulsion particles, (2) evaluating the effect of adding surfactants to the dilute emulsion on spray formation, and (3) considering how nozzle size and liquid pressure influence the breakup mechanism. It is suggested that the wettability of particles may be correlated with their ability to cause perforations if their interfacial tension is not at equilibrium. However, perforations did not appear at the position when the particle diameter was equal to the sheet thickness.
It is suggested that the emulsion particles interact with the local perturbations within the flow. These perturbations grow, causing a hole to develop in the sheet. Adding surfactants to dilute emulsions resulted in a reduction in emulsion particle size, a change in the number of emulsion particles, or a change in the number of perturbations. These changes were associated with a change in spray droplet size.