Abonnement à la biblothèque: Guest
Portail numérique Bibliothèque numérique eBooks Revues Références et comptes rendus Collections
Atomization and Sprays
Facteur d'impact: 1.189 Facteur d'impact sur 5 ans: 1.596 SJR: 0.814 SNIP: 1.18 CiteScore™: 1.6

ISSN Imprimer: 1044-5110
ISSN En ligne: 1936-2684

Volumes:
Volume 29, 2019 Volume 28, 2018 Volume 27, 2017 Volume 26, 2016 Volume 25, 2015 Volume 24, 2014 Volume 23, 2013 Volume 22, 2012 Volume 21, 2011 Volume 20, 2010 Volume 19, 2009 Volume 18, 2008 Volume 17, 2007 Volume 16, 2006 Volume 15, 2005 Volume 14, 2004 Volume 13, 2003 Volume 12, 2002 Volume 11, 2001 Volume 10, 2000 Volume 9, 1999 Volume 8, 1998 Volume 7, 1997 Volume 6, 1996 Volume 5, 1995 Volume 4, 1994 Volume 3, 1993 Volume 2, 1992 Volume 1, 1991

Atomization and Sprays

DOI: 10.1615/AtomizSpr.v9.i2.40
pages 173-192

AIR-ASSIST PRESSURE-SWIRL ATOMIZATION

U. T. Schmidt
Thermal Sciences and Propulsion Center, School of Mechanical Engineering, Purdue University, West Lafayette, Indiana, U.S.A.
Paul E. Sojka
Maurice J. Zucrow Laboratories (formerly Thermal Sciences and Propulsion Center), School of Mechanical Engineering, Purdue University, West Lafayette, Indiana, 47907-2014, USA

RÉSUMÉ

The performance of an air-assist pressure-swirl atomizer and, more important, its limitations are described. The design of the present atomizer is based on a pressure-swirl nozzle, but differs from conventional single-phase pressure-swirl designs in that the liquid film in the exit orifice is stabilized by axially injecting air through the upstream plane of the swirl chamber.
The present study includes drop size data obtained using a Malvern 2600 HSD particle size analyzer. Atomizer performance was assessed using three different nozzle configurations and four different liquids. The drop size data indicate that an increase in liquid supply pressure, liquid mass flow rate, or atomizing air-to-liquid ratio by mass (ALR) leads to a decrease in Sauter mean diameter (SMD). It also shows that spray quality (i.e., mean drop size) is independent of swirl chamber geometry at constant liquid supply pressure and ALR for low-viscosity liquids. Atomizer exit orifice diameter has little effect on SMD when operating at constant liquid supply pressure for these same low-viscosity liquids. However, the effects of liquid mass flow rate and exit orifice diameter are coupled with an increase in exit orifice diameter, leading to an increase in SMD when liquid mass flow rate is constant. The influence of both swirl chamber and exit orifice diameter is enhanced when liquid viscosity climbs to 0.010 kg/m-s. In these cases, SMD increases with a decrease in swirl chamber diameter regardless of whether liquid mass flow rate or supply pressure is kept constant. SMD continues to decrease with a decrease in exit orifice diameter for both the constant liquid mass flow rate and constant liquid supply pressure cases. Finally, the data indicate that mean drop size increases with an increase in either liquid viscosity or surface tension.
A first principles model was developed to explain the observed SMD scaling with operating conditions, nozzle configuration, and liquid physical properties. It combines the classical inviscid analysis for the flow inside a pressure-swirl atomizer with a correlation for the air-to-liquid velocity slip ratio, a geometric model for ligament formation, and a linear fluid mechanical instability analysis to describe ligament breakup. Model predictions reflect the observed SMD scaling with variations in liquid supply pressure, liquid mass flow rate, ALR, swirl chamber diameter, exit orifice chamber diameter, and surface tension. Accuracy is best for intermediate and high liquid delivery rates. Viscosity scaling is not captured accurately. That lack is ascribed to the inviscid internal flow model employed here, which cannot account for the increase in liquid film thickness with an increase in liquid viscosity.


Articles with similar content:

EFFERVESCENT ATOMIZATION OF HIGH-VISCOSITY FLUIDS: PART I. NEWTONIAN LIQUIDS
Atomization and Sprays, Vol.1, 1991, issue 3
Paul E. Sojka, Harry N. Buckner
ATOMIZATION OF GEL FUELS USING IMPINGING-JET ATOMIZERS
International Journal of Energetic Materials and Chemical Propulsion, Vol.10, 2011, issue 1
Gabriela Adler, Anat Desyatkov, Benveniste Natan, Oleg Prokopov
ON THE SHEET BREAKUP OF DIRECT-INJECTION GASOLINE PRESSURE-SWIRL ATOMIZER SPRAYS
Atomization and Sprays, Vol.17, 2007, issue 6
P. W. Loustalan, Martin H. Davy
LIQUID SHEET DISINTEGRATION BY IMPINGING AIR STREAMS
Atomization and Sprays, Vol.1, 1991, issue 2
Arthur H. Lefebvre, J. E. Beck, T. R. Koblish
SPRAY CHARACTERISTICS OF AN OPEN-END SWIRL INJECTOR
Atomization and Sprays, Vol.22, 2012, issue 5
Wei Zhang, Qing-fei Fu, Kun-Da Cui, Li-jun Yang