PREDICTION OF SPRAY ANGLE FROM FLAT FAN NOZZLES

This paper presents a numerical approach to relate the spray angle of a flat fan nozzle to its internal geometry. The effect of changing fou r parameters, the half V-cut angle, the V-cut offset, the input sectio n diameter and the height of the blind end, together with the surface shape immediately upstream of the output orifice have been studied. Te n commercial nozzles from two different nozzle manufacturers have been analysed. The predictions of spray angle for these nozzles were in cl ose agreement with the measured results using a standard spray pattern ator. A parametric study of the nozzle geometry showed that, for the c ase using a simple hemispherical blind end, varying half V-cut angle r esults in a spray with angles ranging from 15 degrees to 120 degrees. Studies of the nozzle design and its effect on the liquid sheet thickn ess showed that, for sprays with the same flow rate and same spray ang le, the thickness of the liquid sheet increased with an increase of th e nozzle input section diameter and vice versa. (C) 1996 Silsoe Resear ch Institute