Measurements of the Spray Angle of Atomizing Jets

Abstract

Liquid jets are considered issuing from single-hole, round nozzles into quiescent gases under conditions such that they break up into a well defined conical spray immediately at the nozzle exit plane. The initial angles of such sprays were measured at room temperature by a spark photography technique. Water, n-hexane, and n-tetradecane at pressures from 11.1 MPa to 107.6 MPa were injected into gaseous N2 at pressures from 0.1 MPa to 4.2 MPa through sixteen nozzles of different geometry. Under the test conditions, the spray angle is found to be a strong function of the nozzle geometry and the gas-liquid density ratio and a weak function of the injection velocity. The measured trends are then discussed in the light of possible mechanisms of the breakup process and shown to be compatible with the aerodynamic theory of surface breakup if modified to account for nozzle geometry effects.