Pressure characteristics at the pour-tube orifice in ultrasonic gas atomization

Abstract Atomization experiments performed with an ultrasonic gas atomization (USGA) device have shown that in some cases back pressure is generated within the atomization die. The metal stream is then pushed upwards, instead of being atomized. Measurements of the back pressures made as a function of the line pressure have shown that gas flow is strongly dependent on the nozzle design, the pour-tube geometry and the inlet gas pressure. When interchangeable nozzle inserts of various shapes are used, the gas flow characteristics are altered. Variations in the insert length may have detrimental effects on the atomization process in some cases. The experiments reported here give evidence that the exact position of the pour tube relative to the gas stream is a crucial parameter when back pressures are to be avoided, and when optimal atomization efficiency is sought. Results of experiments performed to provide relevant information for proper design and performance of an USGA process are presented.