Effect of Aspiration Pressure on Convergent nozzle employed for gas atomization of Liquid Metals

Atomization is often chosen as one of powder production techniques because of high production rates and ability to make alloy powders of desired composition. In gas atomization process, liquid metal is broken into droplets to form powders upon solidification. Gas-metal interaction influences the break-up of liquid stream into droplets. The idea is to transfer kinetic energy from a high velocity jet-gas expanded through a nozzle, to a stream of liquid metal, resulting in fragmentation and break up into metal droplets. Gas atomization process is one of the widely used powder production technique and nozzles play an important role in the gas atomization process. The geometry of nozzles governs the gas to metal interaction. The selection of nozzle type and the flow geometry is the most important preset parameter for atomization process. The design of an atomizing nozzle determines degree of contact of liquid metal with the atomizing gas. Aspiration pressure is the optimum pressure developed at tip of the nozzle (at atomization zone) which will favor gas atomization process. In the present analysis, an attempt was made to analyze effect of atomization pressure and aspiration pressure for Convergent nozzle (C-nozzle) employed for gas atomization process using Computational Fluid Dynamics (CFD) techniques