Effects of prefilmer edge thickness on spray characteristics in prefilming airblast atomization

Abstract

The effects of prefilmer edge thickness on the spray characteristics of a prefilming airblast atomizer were experimentally investigated. The Sauter mean diameter (SMD), variation of the mean diameter with time, and droplet number density were experimentally measured for various prefilmer edge thicknesses and air velocities at various measurement points. The liquid flow rate was kept constant. The effect of prefilmer edge thickness on SMD was large in the primary atomization region, but small in the secondary atomization region. In the primary atomization region, with increasing edge thickness, the droplet size distribution became broader, the SMD dispersion increased, and the droplet number density dispersion decreased. In the secondary atomization region, the SMD dispersion in time was small for all prefilmer edge thicknesses. The effect of prefilmer edge thickness on droplet number density dispersion was small. For a large prefilmer edge thickness, the SMD and the total droplet surface area varied randomly with time, whereas the arithmetic mean surface area was almost constant over the whole sampling period.