Dilute emulsions and their effect on the breakup of the liquid sheet produced by flat-fan spray nozzles

Studies of the effect of dilute emulsions on spray formation by flat-fan no zzles have shown that the presence of emulsion particles changes the mechan ism of liquid sheet breakup. Perforations in the liquid sheet occur at a po sition that is dependent on the nature and the concentration of the emulsif ied cor,components. It has been suggested that perforations occur with part icles of low wettability and when the liquid sheet thickness equals the par ticle diameter. We examined this by (I) investigating the relationship betw een the length of the liquid skeet and the diameter of the emulsion particl es, (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 p articles may be correlated with their ability to cause perforations if thei r interfacial tension is not at equilibrium. However, perforations did riot appear at the position when the particle diameter was equal to the skeet t hickness. II is suggested that the emulsion particles interact with the local perturb ations within the flow. These perturbations grow, causing a hole to develop in the sheet. Adding surfactants to dilute emulsions resulted in a reducti on 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.