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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

1997, Volume7

114 pages

Issue price - $75.00

HOLOGRAPHIC INVESTIGATION OF THE EFFECT OF ELEVATED AMBIENT TEMPERATURE ON THE ATOMIZATION CHARACTERISTICS OF IMPINGING JET SPRAYS

Y. Shen
Department of Mechanical Engineering, University of Illinois at Chicago, Chicago, IL 60607

C. Mitts
Department of Mechanical Engineering, University of Illinois at Chicago, Chicago, IL 60607

Dimos Poulikakos
Laboratory of Thermodynamics in Emerging Technologies, Department of Mechanical and Process Engineering, Institute of Energy Technology, Swiss Federal Institute of Technology (ETH), ETH Center, Zurich, Switzerland

ABSTRACT

A study of impinging jet sprays formed by a pair of 0.8-mm jets impinging at an angle of 90 ° at ambient temperatures from 25 to 250 °C has been conducted using a double-pulse, two-reference-beam holographic technique. The working fluids utilized were water, a 59 wt% aqueous glycerol solution, and ethanol. Velocity measurements and drop size distributions were obtained for various regions of the spray, and the universal root-normal distribution was used as a representation of the cumulative volume distributions. Generally, the qualitative nature of the spray pattern remained the same as temperature increased, but the size of the resulting droplets decreased as a result of evaporation and increased instabilities. Furthermore, the wave structure, which is characteristic of a fully developed impinging jet spray, became less distinct as temperature increased. The average velocity of the particles within a 20 ° envelope of the spray centerline in the dense region was approximately equal to the mean jet velocity. At downstream locations, the average droplet velocity decreased to approximately 65% of the mean jet velocity. In addition to the data obtained, the advantages of using double-pulse holography are highlighted. Namely, spatial and temporal aspects of the entire spray can be obtained simultaneously. This is a powerful feature, especially in light of the ability of holography to be used to analyze dense regions of a spray.