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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| Médium: | Článek |
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International Communications in Heat and Mass Transfer
2010
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| _version_ | 1825719268001447936 |
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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. |
| collection | UM |
| 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. |
| first_indexed | 2024-03-06T05:17:04Z |
| format | Article |
| id | um.eprints-6749 |
| institution | Universiti Malaya |
| last_indexed | 2024-03-06T05:17:04Z |
| publishDate | 2010 |
| publisher | International Communications in Heat and Mass Transfer |
| record_format | dspace |
| spelling | 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 |
| work_keys_str_mv | AT mohammedha experimentalstudyofforcedandfreeconvectiveheattransferinthethermalentryregionofhorizontalconcentricannuli AT campoa experimentalstudyofforcedandfreeconvectiveheattransferinthethermalentryregionofhorizontalconcentricannuli AT saidurrahman experimentalstudyofforcedandfreeconvectiveheattransferinthethermalentryregionofhorizontalconcentricannuli |