Supersonic Nozzle Flow Simulations for Particle Coating Applications: Effects of Shockwaves, Nozzle Geometry, Ambient Pressure, and Substrate Location upon Flow Characteristics

Title
Supersonic Nozzle Flow Simulations for Particle Coating Applications: Effects of Shockwaves, Nozzle Geometry, Ambient Pressure, and Substrate Location upon Flow Characteristics
Authors
이민욱Jung-Jae ParkSam S. YoonHo-Young KimScott C. JamesStephen D. HeisterSanjeev ChandraWoon-Ha YoonDong-Soo ParkJungho Ryu
Keywords
nano-particle coating; nozzle optimization; shockwave; supersonic flow; thin-film deposition
Issue Date
2011-03
Publisher
Journal of thermal spray technology
Citation
VOL 20, NO 3-522
Abstract
Characteristics of supersonic flow are examined with specific regard to nano-particle thin-film coating. Effects of shockwaves, nozzle geometry, chamber pressure, and substrate location were studied computationally. Shockwaves are minimized to reduce fluctuations in flow properties at the discontinuities across diamond shock structures. Nozzle geometry was adjusted to ensure optimal expansion (i.e., P(exit) = P(ambient)), where shock formation was significantly reduced and flow kinetic energy maximized. When the ambient pressure was reduced from 1 to 0.01316 bar, the nozzle's diverging angle must be increased to yield the optimum condition of minimized adversed effects. Beyond some critical distance, substrate location did not seem to be a sensitive parameter on flow characteristics when P(amb) = 0.01316 bar; however, overly close proximity to the nozzle exit caused flow disturbances inside the nozzle, thereby adversely affecting coating gas flow.
URI
http://pubs.kist.re.kr/handle/201004/66127
ISSN
1059-9630
Appears in Collections:
KIST Publication > Article
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