Experimental study of forced and free convective heat transfer in the thermal entry region of horizontal concentric annuli

Forced and free convective heat transfer for thermally developing and thermally fully developed laminar air flow inside horizontal concentric annuli in the thermal entrance length has been experimentally investigated. The experimental setup consists of a stainless steel annulus having a radius ratio...

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Main Authors: Mohammed, H.A., Campo, A., Saidur, Rahman
Format: Article
Published: International Communications in Heat and Mass Transfer 2010
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Online Access:http://eprints.um.edu.my/6749/
http://ac.els-cdn.com/S0735193310000904/1-s2.0-S0735193310000904-main.pdf?_tid=3b235b62-4024-11e2-a2de-00000aab0f02&acdnat=1354853693_a18f2616a06aeff147c7520de4654b13
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author Mohammed, H.A.
Campo, A.
Saidur, Rahman
author_facet Mohammed, H.A.
Campo, A.
Saidur, Rahman
author_sort Mohammed, H.A.
building UM Library
collection Institutional Repository
content_provider Universiti Malaya
content_source UM Research Repository
continent Asia
country Malaysia
description Forced and free convective heat transfer for thermally developing and thermally fully developed laminar air flow inside horizontal concentric annuli in the thermal entrance length has been experimentally investigated. The experimental setup consists of a stainless steel annulus having a radius ratio of 2 and an inner tube with a heated length of 900 mm subjected to a constant wall heat flux boundary condition and an adiabatic outer annulus. The investigation covers Reynolds number range from 200 to 1000, the Grashof number was ranged from 6.2 x 10(5) to 1.2 x 10(7). The entrance sections used were long tube with length of 2520 mm (L/D(h) = 63) and short tube with length of 504 mm (L/D(h) = 12.6). The surface temperature distribution along the inner tube surface, and the local Nusselt number distribution versus dimensionless axial distance Z(t) were presented and discussed. It is inferred that the free convection effects tended to decrease the heat transfer at low Re number while to increase the heat transfer for high Re number. This investigation reveals that the Nusselt number values were considerably greater than the corresponding values for fully developed combined convection over a significant portion of the annulus. The average heat transfer results were correlated in terms of the relevant dimensionless variables with an empirical correlation. The local Nusselt number results were compared with available literature and show similar trend and satisfactory agreement.
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publisher International Communications in Heat and Mass Transfer
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spelling my.um.eprints-67492019-10-25T06:10:49Z http://eprints.um.edu.my/6749/ Experimental study of forced and free convective heat transfer in the thermal entry region of horizontal concentric annuli Mohammed, H.A. Campo, A. Saidur, Rahman TA Engineering (General). Civil engineering (General) TJ Mechanical engineering and machinery Forced and free convective heat transfer for thermally developing and thermally fully developed laminar air flow inside horizontal concentric annuli in the thermal entrance length has been experimentally investigated. The experimental setup consists of a stainless steel annulus having a radius ratio of 2 and an inner tube with a heated length of 900 mm subjected to a constant wall heat flux boundary condition and an adiabatic outer annulus. The investigation covers Reynolds number range from 200 to 1000, the Grashof number was ranged from 6.2 x 10(5) to 1.2 x 10(7). The entrance sections used were long tube with length of 2520 mm (L/D(h) = 63) and short tube with length of 504 mm (L/D(h) = 12.6). The surface temperature distribution along the inner tube surface, and the local Nusselt number distribution versus dimensionless axial distance Z(t) were presented and discussed. It is inferred that the free convection effects tended to decrease the heat transfer at low Re number while to increase the heat transfer for high Re number. This investigation reveals that the Nusselt number values were considerably greater than the corresponding values for fully developed combined convection over a significant portion of the annulus. The average heat transfer results were correlated in terms of the relevant dimensionless variables with an empirical correlation. The local Nusselt number results were compared with available literature and show similar trend and satisfactory agreement. International Communications in Heat and Mass Transfer 2010 Article PeerReviewed Mohammed, H.A. and Campo, A. and Saidur, Rahman (2010) Experimental study of forced and free convective heat transfer in the thermal entry region of horizontal concentric annuli. International Communications in Heat and Mass Transfer, 37 (7). pp. 739-747. ISSN 0735-1933, DOI https://doi.org/10.1016/j.icheatmasstransfer.2010.04.007 <https://doi.org/10.1016/j.icheatmasstransfer.2010.04.007>. http://ac.els-cdn.com/S0735193310000904/1-s2.0-S0735193310000904-main.pdf?_tid=3b235b62-4024-11e2-a2de-00000aab0f02&acdnat=1354853693_a18f2616a06aeff147c7520de4654b13 10.1016/j.icheatmasstransfer.2010.04.007
spellingShingle TA Engineering (General). Civil engineering (General)
TJ Mechanical engineering and machinery
Mohammed, H.A.
Campo, A.
Saidur, Rahman
Experimental study of forced and free convective heat transfer in the thermal entry region of horizontal concentric annuli
title Experimental study of forced and free convective heat transfer in the thermal entry region of horizontal concentric annuli
title_full Experimental study of forced and free convective heat transfer in the thermal entry region of horizontal concentric annuli
title_fullStr Experimental study of forced and free convective heat transfer in the thermal entry region of horizontal concentric annuli
title_full_unstemmed Experimental study of forced and free convective heat transfer in the thermal entry region of horizontal concentric annuli
title_short Experimental study of forced and free convective heat transfer in the thermal entry region of horizontal concentric annuli
title_sort experimental study of forced and free convective heat transfer in the thermal entry region of horizontal concentric annuli
topic TA Engineering (General). Civil engineering (General)
TJ Mechanical engineering and machinery
url http://eprints.um.edu.my/6749/
http://ac.els-cdn.com/S0735193310000904/1-s2.0-S0735193310000904-main.pdf?_tid=3b235b62-4024-11e2-a2de-00000aab0f02&acdnat=1354853693_a18f2616a06aeff147c7520de4654b13
url_provider http://eprints.um.edu.my/