Atomization of Liquid Droplets Due to Air Streams. 2nd Report. Deformation of a Liquid Droplet.

Abstract

This paper describes the effect of deformation of a liquid droplet due to its displacement when exposed to air streams. Experiments were conducted using a 60 mm×150 mm cross-sectional and 500 mm long horizontal air-suction wind tunnel. Uniformly sized liquid droplets produced by a longitudinal vibration of the nozzle or by dripping uniform size drops from the nozzle were used. The deformation and the displacement of liquid droplets due to air streams were observed using a stroboscope and were photographed by a camera. The liquid droplets exposed to air streams were deformed ; that is, the longitudinal droplet's diameter which is the normal size to the air stream direction, or the curvature of a drop at the stagnation point, etc are changed. As the projection area of a droplet exposed to air streams is expected to greatly influence the displacement, the drag coefficient, the breakup time, and so on, the longitudinal droplet diameters are precisely measured. The experimental equation for the dimensionless displacement and dimensionless time of liquid droplets submitted in the first report is available for droplets with small deformations. The deformation rate of the longitudinal droplet's diameter as applicable to the experimental equation is investigated quantitatively in detail. The relationship between the Weber number and the maximum/minimum dimensionless longitudinal droplet's diameters is surveyed. The maximum dimensionless longitudinal droplet diameter increases as the Weber number increases. The highest Weber number available to the experimental equation decreases with increasing the droplet diameters.