Measurements of drop size at the spray edge near the nozzle in atomizing liquid jets

Journal Article · Tue Apr 01 04:00:00 EST 1986 · Phys. Fluids; (United States)

DOI:https://doi.org/10.1063/1.865689· OSTI ID:5900778

Wu, K; Reitz, R D; Bracco, F V

The drop size distribution was measured from back-lighted spark photographs at the edge of steady sprays in the immediate vicinity of the nozzle exit. The conditions of these liquid-into-gas sprays were such that the outer surface of the liquid jets broke up into small drops at the nozzle exit. The objective was to elucidate the mechanism of breakup. At room temperature, n-hexane and n-tetradecane at pressures from 2.86 to 9.76 MPa were injected into gaseous nitrogen at 1.48 to 2.86 MPa through three straight cylindrical nozzles of different diameters, 127 and 335 ..mu..m, and length-to-diameter ratios, 4 and 10. In all cases, the drop sizes could be fitted satisfactorily with a chi-square distribution with degree of freedom equal to 28. The Sauter mean drop diameter and other average diameters were found to decrease with increasing injection velocity and decreasing liquid surface tension, to be insensitive to nozzle diameter and length, and to increase slightly with increasing gas density. The trends and magnitudes are in agreement with those predicted by the supplemented aerodynamic theory of surface breakup if it is assumed that between the jet surface where the drops are formed, that is not visible, and the edge of the spray, where the measurements were made, drops undergo collisions and coalescence. In this region of dense sprays, drop coalescence leads to a rapid increase in drop size, particularly in high gas densities.

• Research Organization: Mechanical and Aerospace Engineering Department, Princeton University, Princeton, New Jersey 08544
• DOE Contract Number: AC04-81AL16338
• OSTI ID: 5900778
• Journal Information: Phys. Fluids; (United States), Journal Name: Phys. Fluids; (United States) Vol. 29:4; ISSN PFLDA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360603* -- Materials-- Properties
ALKANES
ATOMIZATION
CONFIGURATION
CYLINDRICAL CONFIGURATION
DISTRIBUTION
DROPLETS
ELEMENTS
FLUID INJECTION
FLUIDS
GASES
HEXANE
HYDROCARBONS
JETS
MEDIUM PRESSURE
MEDIUM TEMPERATURE
NITROGEN
NONMETALS
NOZZLES
ORGANIC COMPOUNDS
PARTICLES
PHOTOGRAPHY
SIZE
SPRAYS