THERMAL SCIENCE

International Scientific Journal

Ali Hajimohammadi

,

Mehran Rajabi Zargarabadi

,

Javad Mohammadpour

A DETAILED ANALYSIS OF FLOW AND HEAT TRANSFER CHARACTERISTICS UNDER A TURBULENT INTERMITTENT JET IMPINGEMENT ON A CONCAVE SURFACE

ABSTRACT
A computational study is carried out of the 3-D flow field and heat transfer under a turbulent intermittent circular jet impingement on a concave surface. The control-volume procedure with the SIMPLE algorithm is employed to solve the unsteady RANS (use full form) equations. The RNG k-ε model is implemented to simulate turbulence due to its success in predicting similar flows. The numerical results are validated by comparing them with the experimental data. The effects of jet Reynolds number and oscillation frequency on the flow and heat transfer are evaluated. The profiles of instantaneous and time-averaged Nusselt numbers exhibit different trends in axial, x-directions and circumferential, s-directions. It is found that increasing frequency from 50 to 200 Hz results in considerable time-averaged Nusselt number enhancement in both axial and curvature directions. The intermittent jet at a frequency of 200 Hz enhances the total average Nusselt number by 51.4%, 40%, and 33.7% compared to the steady jet values at jet Reynolds numbers of 10000, 23000, and 40000, respectively. In addition, a correlation for the average Nusselt number is proposed depending on the Reynolds number and the Strouhal number.
KEYWORDS
Pulsating impinging jet, heat transfer, Intermittent jet, Concave surface, nusselt number, Strouhal number
PAPER SUBMITTED: 2020-07-29
PAPER REVISED: 2021-04-25
PAPER ACCEPTED: 2021-05-05
PUBLISHED ONLINE: 2021-12-04
DOI REFERENCE: https://doi.org/10.2298/TSCI200729334H
CITATION EXPORT: view in browser or download as text file
THERMAL SCIENCE YEAR 2022, VOLUME 26, ISSUE Issue 2, PAGES [1709 - 1720]
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A detailed analysis of flow and heat transfer characteristics under a turbulent intermittent jet impingement on a concave surface

© 2024 Society of Thermal Engineers of Serbia. Published by the Vinča Institute of Nuclear Sciences, National Institute of the Republic of Serbia, 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