Characteristics of the Endogenous Rotation-Induced Airflow Field and Its Influence on Droplets Produced by a Rotating Disk

Abstract

Rotating-disk centrifugal atomization is an effective technique to break up highly viscous liquid into droplets with a narrow size distribution. However, dispersed spray fields coupled with their high initial velocities limit the application of this method in the directional spray, enlarge the volume of the atomization chamber, and increase the expenses for the protective gas. Herein, a novel atomization technique to control the spray field produced by the rotating disk is proposed. By regulating the endogenous rotational-induced airflow, the spray field can be controlled more efficiently and at a lower cost. Hence, the rotation-induced airflow field and its influence on the atomized droplets were investigated using a schlieren system, laser particle size analyzer, a particle image velocimetry (PIV) system, and a numerical simulation method. Two patterns, namely, symmetric and asymmetric flow patterns, were observed around the rotating-disk centrifugal atomizer, and their presence depended on the adjustment of the rotational speed and the peripheral geometrical parameter λ. In the asymmetric flow pattern, the deflective jet flow could direct the droplet movement directions from radial outward to axial backward, producing a more concentrated and directional spray field, but enlarge the mean diameter of atomized droplets.