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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

120 pages

Issue price - $75.00

GASOLINE INJECTION AGAINST SURFACES AND FILMS

C. Arcoumanis
School of Engineering, City University, London, United Kingdom

D. S. Whitelaw
Thermofluids Section, Department of Mechanical Engineering, Imperial College of Science, Technology and Medicine, London, United Kingdom

J. H. Whitelaw
Thermofluids Section, Department of Mechanical Engineering, Imperial College of Science, Technology and Medicine, London SW7 2BX, United Kingdom

ABSTRACT

The velocity, diameter, and flux of droplets in a rectangular wind tunnel simulating an engine port have been measured in and downstream of the region of impingement of an isooctane spray directed at 20° to the bottom flat surface, both at room temperature, with a vertical distance from the injector to the wall of 32 mm, an injection pressure of 3 bar, and a frequency of injection of 10 Hz. The cross-stream airflow velocities were 5 and 15 m/s and the injection periods 10 and 20 ms. The results show that the spray impinged on the surface, which became wet as the spray continued so that small-diameter droplets formed a cloud above the plate and immediately downstream of the location of impingement, with stronger convection of these small droplets with higher air velocity. The cloud was denser with a larger quantity of injected fluid and with lower air velocity. Also, the wall film survived from one injection to the next with lower air velocity and became thicker, so that splash atomization generated large droplets for some distance downstream and probably gave way to film stripping with slightly smaller droplets immediately above the film. Similar results, with larger concentrations of larger droplets, can be expected with smaller times between injections, and a hot surface will tend to evaporate the liquid so that the film will decrease in thickness, with reduction in secondary atomization.