Theoretical analysis of free-surface film flow on the rotary granulating disk in waste heat recovery process of molten slag

This paper proposed a simple theoretical model to characterize the continuous free-surface film flow on the rotary disk in waste heat recovery process of molten slag by the method of order of magnitude analysis. Liquid film thickness, mean radial velocity and degree of tangential slippage have been analyzed based on the proposed model. The model indicates that the free-surface film flow on the rotary disk is governed primarily by the balance between Coriolis and centrifugal forces and viscous drag after the hydraulic jump. The inertia force contributes primarily nearby the center of the rotary disk. It is revealed that the liquid film thickness distribution on a rotary disk is mainly determined by the volume flow rate, kinematic viscosity of molten slag and the rotational speed of disk. Compared with the existing results and CFD simulation data, the model shows good performance. As indicated by the CFD simulation results, the hydraulic jump region has no influence on the liquid flow after the hydraulic jump, hence has none effect on the granulation performance of molten slag.