Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9796704 | Materials Science and Engineering: A | 2005 | 9 Pages |
Abstract
A high-speed cinematographic footage of a 304L stainless steel gas atomization, recorded at the National Institute of Standard and Technology (NIST), was analyzed using a discrete Fourier transform (DFT) algorithm. The analysis showed the gas atomization process possesses two prominent frequency ranges of melt oscillation (pulsation). A low-frequency oscillation in the melt flow occurring between 5.41 and 123Â Hz, with a dominant frequency at 9.93Â Hz, was seen in the recirculation zone adjacent to the melt orifice. A high-frequency melt oscillation range was observed above 123Â Hz, and was more prominent one melt-tip-diameter downstream in the melt atomization image than upstream near the melt tip. This high-frequency range may reflect the melt atomization frequency used to produce finely atomized powder. This range also included a prominent high frequency at 1273Â Hz, which dominated in the image further away downstream from the melt tip. This discrete high-frequency oscillation is most probably caused by the aeroacoustic “screech” phenomenon, intrasound (<20Â kHz), a result of the atomizing gas jets undergoing flow resonance. It is hypothesized that this discrete intrinsic aeroacoustic tone may enhance melt breakup in the atomization process with evidence of this fact in the melt images.
Related Topics
Physical Sciences and Engineering
Materials Science
Materials Science (General)
Authors
Jason Ting, Jeffery Connor, Stephen Ridder,