Inscrição na biblioteca: Guest
Portal Digital Begell Biblioteca digital da Begell eBooks Diários Referências e Anais Coleções de pesquisa
Heat Transfer Research
Fator do impacto: 0.404 FI de cinco anos: 0.8 SJR: 0.264 SNIP: 0.504 CiteScore™: 0.88

ISSN Imprimir: 1064-2285
ISSN On-line: 2162-6561

Volumes:
Volume 50, 2019 Volume 49, 2018 Volume 48, 2017 Volume 47, 2016 Volume 46, 2015 Volume 45, 2014 Volume 44, 2013 Volume 43, 2012 Volume 42, 2011 Volume 41, 2010 Volume 40, 2009 Volume 39, 2008 Volume 38, 2007 Volume 37, 2006 Volume 36, 2005 Volume 35, 2004 Volume 34, 2003 Volume 33, 2002 Volume 32, 2001 Volume 31, 2000 Volume 30, 1999 Volume 29, 1998 Volume 28, 1997

Heat Transfer Research

DOI: 10.1615/HeatTransRes.2011001197
pages 199-216

Heat Transfer Enhancement in a Narrow Concentric Annulus in Decaying Swirl Flow

Ali M. Jawarneh
Department of Mechanical Engineering, The Hashemite University

RESUMO

The characteristics of decaying swirling flows and forced convective heat transfer on the conditions of both laminar and turbulent flow in a narrow concentric annulus were simulated. The governing equations are solved numerically via a finite volume method. A uniform wall temperature at the inner wall and adiabatic conditions at the outer wall are considered as thermal boundary conditions. Solutions for the axial and swirl velocity distributions and the Nusselt number are obtained for different values of the inlet swirl number and the Reynolds number. Simulations show that the inlet swirl number have great influences on the heat transfer characteristics. Under both developing laminar and developed turbulent flow conditions, the increases of the inlet swirl number will enhance the heat transfer. When the inlet swirl number increases it increases the axial velocity near the wall and reduces it at the mid-gap to achieve the conservation of mass due to the existence of secondary flows in the annulus due to centrifugal forces. The increase of the near-wall velocity, in turn, produces larger temperature gradients and a higher heat transfer rate. The swirl velocity profiles decay gradually downstream as a result of friction which leads to damping of the tangential velocity. The swirl has a pronounced effect on the turbulent kinetic energy which is increased evidently with the swirl number. Obviously, a higher turbulence level leads to a considerable improvement in the heat transfer rate. Turbulence level improvement can be attributed to the high velocity gradients. Numerical results show that the turbulent kinetic energy is lower in the mid-gap and higher in the near-wall regions. Moreover, the turbulent structures near the outer wall are more activated than those near the inner wall. The comparison between predicted and experimental data of average Nusselt numbers was found to be in good agreement.


Articles with similar content:

EFFECTS OF INLET SWIRL ON THE PERFORMANCE OF ANNULAR JET PUMP
Turbulence and Shear Flow Phenomena -1 First International Symposium, Vol.0, 1999, issue
Tohru Maeda, Osamu Kitamura , Makoto Yamamoto
EFFECTS OF INLET SWIRL ON THE PERFORMANCE OF ANNULAR JET PUMP
TSFP DIGITAL LIBRARY ONLINE, Vol.1, 1999, issue
Tohru Maeda, Osamu Kitamura , Makoto Yamamoto
LARGE EDDY SIMULATION OF FLUID INJECTION UNDER TRANSCRITICAL CONDITIONS: EFFECTS OF PSEUDOBOILING
Heat Transfer Research, Vol.48, 2017, issue 17
Maozhao Xie, Wu Wei, Ming Jia
INVESTIGATION ON SUPERCRITICAL FLUIDS HEAT TRANSFER DETERIORATION AND ITS MITIGATIONS
International Heat Transfer Conference 16, Vol.20, 2018, issue
Eze Chika, Hui Cheng, Jiyun Zhao
Momentum and Heat Transfer in a Buoyant Turbulent Swirling Jet
International Journal of Fluid Mechanics Research, Vol.33, 2006, issue 3
M. A. Halim, Harmindar S. Takhar, Rama Subba Reddy Gorla