CFD Modeling of Melt Spreading Behavior on Spinning Discs and Cups for Centrifugal Granulation of Molten Slag

Abstract

The spreading behaviors of molten slag on spinning discs and cups were studied through performing free surface flow numerical simulations by means of computational fluid dynamics (CFD) modeling technique. In this work, liquid slag film thickness at the edge of the spinning discs and cups was predicted by using the CFD model, since the slag film thickness has a predominant influence on the size of the slag granules produced after the slag film breakup. The effects of the shape of discs and cups and the operating conditions (slag flowrate and spinning speed) on the slag film thickness were examined. Flat surface disc, disc with curved surface, and cups with different sidewall height and taper angle were investigated. It was found from the modeling results that, under the same slag flowrate and spinning speed, the larger the wetting area of the slag on the discs and cups, the smaller the slag film thickness. For the same size (radius) discs and cups, the slag film thickness on the flat surface disc is larger than those on the cup and the curved surface disc. Furthermore, the film thickness on the cup is larger than that on the curved surface disc. The reason is that the cup has a sharp corner and a sidewall that impose a larger resistance to the slag flow, whereas the curved surface disc has a smooth surface that has a smaller resistance to the slag flow.