THERMAL SCIENCE

International Scientific Journal

EFFECTS OF DIFFERENT MEAN VELOCITY RATIOS ON DYNAMICS CHARACTERISTICS OF A COAXIAL JET

ABSTRACT
The flow field of a coaxial jet configuration having inner and outer diameter ratio Di /Do = 0.33 is studied for four values of the velocity ratios and m = Ui /Uo = 5.17, 1.13, 0.77, and 0.54. The profiles of the mean axial velocity, of the axial turbulence intensities, and of the shear stress are described for the initial and fully zones. The obtained results show the inner potential core length of the coaxial jet strongly depends on the velocity ratio while the outer potential core for jets having velocity ratios greater than unity seems to be insensitive to the velocity ratio. As expected, the inner jet core length is seen to decrease with decreasing velocity ratio; jets with velocity less than unity develop faster than those with m greater than unity and the Reynolds stress show a zero-crossing in the near-region. .
KEYWORDS
PAPER SUBMITTED: 2008-03-07
PAPER REVISED: 2008-03-15
PAPER ACCEPTED: 2008-05-15
DOI REFERENCE: https://doi.org/10.2298/TSCI0802049M
CITATION EXPORT: view in browser or download as text file
THERMAL SCIENCE YEAR 2008, VOLUME 12, ISSUE 2, PAGES [49 - 58]
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© 2019 Society of Thermal Engineers of Serbia. Published by the Vinča Institute of Nuclear Sciences, Belgrade, Serbia. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International licence