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Atomization and Sprays

Journal of the International Institutes for Liquid Atomization and Spray Systems

ISSN for PRINT: 1045-5110

Institutional price:	$787.00
Issues per year:	8

Best Paper Award Selection - Editorial Board Site

2007, Volume17

96 pages

Issue price - $109.00

EXPERIMENTAL STUDY OF COAXIAL ATOMIZERS SCALING. PART II: DILUTED ZONE

Bertrand Leroux
Air Liquide, Centre de Recherche Claude Delorme, Les Loges en Josas, BP 126, 78350 Jouy en Josas, France

Olivier Delabroy
Air Liquide, Centre de Recherche Claude Delorme, Les Loges en Josas, BP 126, 78350 Jouy en Josas, France

Francois Lacas
Laboratoire EM2C, C.N.R.S., Ecole Centrale Paris, Grande Voie des Vignes, 92295 Châtenay-Malabry, France

ABSTRACT

Coaxial injectors find many applications in industrial burners or rocket engines. Scaling these devices is therefore an important challenge for burner designers. Theoretical scaling relations for spray properties have been proposed by several authors. Systematic experimental study of gaseous flow properties is already available in the literature. We have found it useful to perform a systematic experimental study of liquid physical properties and injector dimensions, which are typical scaling parameters for applications. The experimental setup used in the present work enables nine different geometrical configurations and a set of various liquid mixtures. Averaged droplets' size and velocities were measured using phase Doppler anemometry. Our experimental results confirm the scaling rules based on the capillary instability theory for the primary atomization zone. Different results are found for the two main atomization regimes: fiber and superpulsating modes. The characteristics of the spray produced in the fiber mode are strongly linked to primary atomization. The superpulsating mode provides a better quality spray, in terms of averaged droplets diameter, but is more dependent on secondary atomization phenomena. Finally, correlations involving momentum flux ratio, Weber number, gaseous flow Reynolds number, and diameter ratio are proposed. They complete the correlations of the literature involving liquid and gaseous flow densities.