Collection Efficiency of Spray Droplets on Vertical Targets

A computational fluid dynamics program (FLUENT) was used to determine the effects of several variables on collection efficiencies of spray droplets directed horizontally toward vertical targets in turbulent air. Variables were: droplet diameter (10 to 600 mm), wind velocity (0.5 to 8.0 m/s), turbulence intensity (5 to 80%) and target width (6.35 to 50.8 mm). An equation (r2 = 0.94) was developed to predict the collection efficiencies of water droplets for the variables. Collection efficiency increased with increasing droplet size, wind velocity, and target width, but decreased with increasing turbulence intensity. Collection efficiencies calculated with FLUENT were very close to those determined experimentally in a wind tunnel. The maximum difference between experimental and calculated collection efficiencies was 11.1% for all experimental conditions.