MECHANISMS AND CHARACTERISTICS OF SPRAY FORMATION WITH FLOW FOCUSING IN A NEW AIR-ASSIST MICRO-ATOMIZER

摘要

The atomization mechanisms and characteristics of a new air-assist micro-atomizer (AMA) fabricated via MEMS machining are described. Observations show that the breakup regimes can be described by the mechanisms involved with the laminar jet disintegration, aerodynamic disintegration and turbulent mode based on the atomizing pressure and Weber number. A new phenomenon of flow branching of the liquid jet emanating from the atomizer was also observed. The ratio of liquid-to-gas flow rate determines the spreading angle and droplets size of the branched liquid streams. It is also found that the flow focusing mechanism resulted in the mono-dispersed droplets stream. Furthermore, the micro spray with mean droplet size of 5μm can be obtained by adjusting the atomization pressure. It is very useful in the applications of sample introduction in inductively coupled plasma mass spectrometry (ICP-MS) and medical inhalation devices.