THE GAS VELOCITY PROFILE OF A FREE-FALL ATOMIZER AND ITS RELATION TO SOLIDIFICATION MICROSTRUCTURE OF COLLECTED SPRAY DROPLETS OF 2014-ALUMINUM-ALLOY

The gas flow field of a free-fall atomizer was measured in three dimen sions using hot wire anemometry and corresponding measurements were ta ken using a Pitot tube to confirm axial now velocities. The measuremen ts show good agreement with predictions of fluid flow modelling. 2014 aluminium alloy spray droplets collected in water or cooled methanol a t the position of a spray deposition substrate, under typical atomizat ion conditions, show a dendrite cell size typical of gas-quenched drop lets for droplet sizes less than 50 mu m, while collected droplets les s than 200 mu m in size show values of cell size significantly smaller than gas-quenched droplets of the same size.