Fuel atomization in a flowing airstream

Since in some modern turbofan engines the primary zone velocity is high enough to affect appreciably the mean drop size of fuel injected through a swirl atomizer, an experiment was designed to obtain accurate data on the influence of the velocity of an airstream on the mean drop size and size distribution of fuel drops injected into it. Kerosene fuel was sprayed in the direction of an airstream in a test section; drop sizes were measured by a light-scattering technique while drop size distribution was measured with a probe in which liquid nitrogen froze the fuel drops, which were then collected in a nitrogen-cooled perspex pot and photographed through a microscope. Results indicated that atomization quality is improved by increases in fuel injection pressure and reduction in atomizer flow number, and also demonstrated that an increase in air velocity reduces the mean drop size.