Abstract

Atomizers for molten metals are used extensively for industrial and research purposes; however, the phenomena governing atomizer design - the interaction between fluids and the pressure field developed - and performance are less understood. In this article, the phenomena governing confined and free-fall atomizer behavior and performance are studied to develop engineering rules for atomizer design. The behavior and performance of confined and free-fall atomizers, such as liquid flow rate and fineness of atomized powders, are strongly dependent on the aerodynamic pressure field (APF) developed in the atomization region. The aerodynamic pressure field defines the operational mode of an atomizer: aspirating, gravity/aspirating, or gravity. Confined atomizers can only operate in aspirating mode, since the pressure field has a wide aspirating region. Free-fall atomizers can operate in either gravity or mixed gravity/ aspirating mode, since the pressure field exhibits a narrow aspirating region followed by a flat and low-pressurization one. A calculation methodology was developed on the basis of Lubanska's equation to evaluate the required gas flow, the total area of atomizer nozzles, the required aspiration, and the liquid delivery tube tip positions.