Atomization characteristics of high-flow variable-orifice flooding nozzles

Droplet spectra factors for variable-orifice flooding nozzles in quasi-stat ic air were investigated to possibly aid the reduction of spray drift, and to provide a basis for future atomizer design. A laser-diffraction instrume nt measured the droplet size spectra of water sprays through orifices with diameters ranging from 1.14 to 6.35 mm. Spray discharge flow rates up to 40 L min(-1) were measured with a Coriolis-type sensor Nozzles produced an ar ray of droplet size spectra with volume median diameters (D-v0.5) ranging f rom 296 to 1062 mum. For single-orifice flooding nozzles, orifice diameter was the most important factor positively correlated with droplet size spect ra factors, except the D-v0.9. For flooding nozzles utilizing two orifices in series, the magnitude of difference between the two orifice diameters wa s the most important factor positively correlated with droplet size spectra factors. In addition, two-orifice flooding nozzles had strong negative cor relations between pressure and droplet size factors, whereas single-orifice flooding nozzles had strong positive correlations between flow rate and dr oplet size factors. A unique flow-pressure phenomenon, in which flow decrea sed or remained steady with increasing pressure, was observed for some orif ices and pressures, possibly due to orifice inlet limiting conditions. The use of regression coefficients predicted most droplet size spectra factors with coefficients of determination (r(2))ranging from 0.72 to 0.91, except for low r(2) values (0.11 to 0.50) associated with the D-v0.9 of single-ori fice nozzles.