THERMAL SCIENCE

International Scientific Journal

Fatma B.m. Ahmed

,

Nobuyuki Kawahara

,

Eiji Tomita

BINARY COLLISIONS AND COALESCENCE OF DROPLETS IN LOW-PRESSURE FUEL INJECTOR

ABSTRACT
The phenomena of binary collisions and coalescence of droplets was investigated from experimental studies but still are missing from real applications such as from fuel injector. The main purpose of the current study is to investigate the phenomena of binary collisions and coalescence of droplets from a practical port fuel injector. To accomplish this, direct microscopic images are taken from high speed video camera coupled with a long-distance microscope and Barlow lens using the backlighting method. Experimental optimization of the spatial resolution and the depth -of -field of the long-distance microscope and Barlow lens are achieved. Experimental results from the direct microscopic images are compared with predictions from empirical equations for different collision regimes. Droplet sizes and velocities of experimental coalescence droplets from collisions are compared with the values predicted by the equations. The main results of this study are: The probability of collision and coalescence is very low in a port fuel injector. The tangential velocity components of small droplets play an essential role in shape deformation during collisions and coalescence of the droplets. The previous published empirical equations to calculate dimensionless parameters, the Weber number, the droplet diameter ratio, and impact parameter are applicable to the coalescence of droplets in a port fuel injector.
KEYWORDS
direct microscopic image, collision, coalescence, port fuel injector, droplet collision regimes, high-speed video camera
PAPER SUBMITTED: 2019-11-20
PAPER REVISED: 2020-05-25
PAPER ACCEPTED: 2020-05-30
PUBLISHED ONLINE: 2020-06-07
DOI REFERENCE: https://doi.org/10.2298/TSCI191120185A
CITATION EXPORT: view in browser or download as text file
THERMAL SCIENCE YEAR 2021, VOLUME 25, ISSUE Issue 3, PAGES [1963 - 1973]
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Binary collisions and coalescence of droplets in low-pressure fuel injector

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