Convective heat transfer characteristics in the rectangular packed beds with asymmetric heating

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" Convective heat transfer characteristics in the rectangular packed beds with asymmetric heating "
B. A. Abu-Al-Saud

Document Type	:	Latin Dissertation
Language of Document	:	English
Record Number	:	1112831
Doc. No	:	TLpq304410038
Main Entry	:	B. A. Abu-Al-Saud
Title & Author	:	Convective heat transfer characteristics in the rectangular packed beds with asymmetric heating\ B. A. Abu-Al-Saud
College	:	King Fahd University of Petroleum and Minerals (Saudi Arabia)
Date	:	1997
student score	:	1997
Degree	:	M.S.
Page No	:	132
Abstract	:	This study casts light on the heat transfer in asymmetrically heated packed ducts in which a constant heat flux is supplied from the top while the other walls are insulated. Two different ducts with aspect ratio W/H of 8 and 4 respectively have been used. Two different types of packing have been used. The first one is the expanded polystyrene sphere in three different sizes while the second one is the polyvinyl chloride Raschig ring in two different sizes. Both air and wall temperatures were measured at various positions for different air flow rates and different heat fluxes. This was done for both empty and packed ducts. This study presents both experimental and numerical analysis for the steady state case. The effect of both type and size of packing in addition to the aspect ratio of the duct on the heat transfer coefficient has been studied. A comparison between the measured and predicted values of air temperatures is shown. This study gives a correlation for Nusselt number that can be used for 96 < Re{p}\ < 5755 and 4.5 < d{e}/d{p}\ The following correlation is obtained for the spherical packing based on 33 experiment runs:usd\rm Nu = 1.4554 Re\sbsp{\rm H}{0.81}\ e\ \sp{-7.8241({D\sb{p}\over D\sb{\rm e}})}usdusdwhile for the Raschig ring, the following correlation is obtained based on 21 runs:usdusd\rm Nu = 6.7833 Re\sbsp{\rm H}{0.5209}\ e\ \sp{-7.0273({D\sb{\rm p}\over D\sb{\rm e}})}usdusd It was found that as Reynolds number increases the Nusselt number also increases. Also, Nu{p}/Nu{e} increases with the increase of D{p}/D{e}. The heat transfer coefficient is found to be three times higher for the packed ducts than that of the empty ducts. Experimental investigation of unsteady forced convection heat transfer in the packed duct with W/H = 4 is also presented.
Subject	:	Applied sciences
	:	Chemical engineering