Abonnement à la biblothèque: Guest
Portail numérique Bibliothèque numérique eBooks Revues Références et comptes rendus Collections
Heat Transfer Research
Facteur d'impact: 0.404 Facteur d'impact sur 5 ans: 0.8 SJR: 0.264 SNIP: 0.504 CiteScore™: 0.88

ISSN Imprimer: 1064-2285
ISSN En ligne: 2162-6561

Volumes:
Volume 51, 2020 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.2016010684
pages 529-548

EXPERIMENTAL DETERMINATION OF THE WETTED AREA OF A FALLING FILM ON THE OUTSIDE OF HORIZONTAL TUBES USING IMAGE PROCESSING AND HEAT TRANSFER ANALYSIS

Cenk Onan
Department of Mechanical Engineering, Yildiz Technical University, TR-34349 Besiktas, Istanbul, Turkey
Derya B. Ozkan
Department of Mechanical Engineering, Yildiz Technical University, TR-34349 Besiktas, Istanbul, Turkey

RÉSUMÉ

Falling film is observed in closed type cooling towers, evaporative condensers and absorption cooling. In this study, the aim was to increase the amount of evaporating water on the tube surface during falling film. To increase the area of wetness, different groove forms were used, which were placed longitudinally or helically on horizontal tubes. The groove geometries were triangular, trapezoidal, round and square. In the experiments, the area of wetness was measured by generating falling film type flow on horizontal tubes with these four different groove geometries. The falling film type flow was generated using dyed water to measure the area of wetness. Photographs were taken using a high-speed camera to determine the area of wetness in the tubes. The photographs were processed using MATLAB, and it was concluded that the helically trapezoid geometry tube had the maximum rate of wet area of 74% and that the longitudinal trapezoid groove geometry tube had the minimum rate of 46%. Afterwards, the amounts of evaporating water, heat convection coefficients and Nusselt number values were determined. The results indicated that as the temperature of the feeding water increased, the amount of evaporating water also increased. The Nusselt correlation was observed at different temperatures of feeding water between 30 °C and 40 °C and depending on the Rew and Rea of the falling film. It was determined that while Rew was between 100 and 350, the observed heat convection coefficient was between 15 and 55 W/m2·K for the simultaneous heat and mass transfer.


Articles with similar content:

The effect of micro- surface treatment on heat and mass transfer performance for falling film absorption process
International Heat Transfer Conference 12, Vol.30, 2002, issue
Chan Woo Park, Jin-Kyeong Kim, Yong Tae Kang
CONDENSATION HEAT TRANSFER AND PRESSURE DROP OF R-410A IN INTERNALLY ENHANCED FLAT ALUMINUM MULTI-PORT TUBES
Journal of Enhanced Heat Transfer, Vol.22, 2015, issue 6
Nae-Hyun Kim
Investigation of thick polymer film promoting dropwise condensation mode on dropwise and film coexisting surfaces
International Heat Transfer Conference 12, Vol.44, 2002, issue
Xiao-Bo Zhu, Dunqi Xu, Jia-Ming An, Jia-Bin Chen, Xuehu Ma, Jifang Lin
MEASUREMENT OF SURFACE TENSION OF MIXTURES OF TFE AND NMP
International Heat Transfer Conference 11, Vol.9, 1998, issue
Naotsugu Isshiki, K. Ogawa, H. Koga
CONDENSATION OF ATMOSPHERIC PRESSURE STEAM ON INTEGRAL-FIN TUBES - EFFECT OF FIN HEIGHT AND VAPOUR VELOCITY
International Heat Transfer Conference 13, Vol.0, 2006, issue
S. Namasivayam