ON THE CHARACTERISTICS OF TRANSITIONAL PHENOMENA IN HEAT TRANSFER FROM EXTENDED SURFACES TO BOILING LIQUID

The aim of this research is to obtain the maximum steady state heat transfer used aluminum alloy extended surfaces which obtain the optimal design for these fins. For three cases, (according to both dimension and direction of the extended surfaces): vertical fins extended from horizontal base, vertical fins extended from vertical base , and horizontal fins extended from vertical base, the natural convective, conductive and radiative heat transfer was studied experimentally and respectively the comparison between these cases were achieved. The parameters studied were distance between fins, fin length fin thickness and fin protrusion.

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Heat Transfer from Extended Surfaces

Heat Transfer ◽

10.1007/978-3-030-58338-5_4 ◽

2021 ◽

pp. 97-150

Author(s):

S. P. Venkateshan

Keyword(s):

Heat Transfer ◽

Extended Surfaces

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Heat Transfer Characteristics of Liquid-Driven Swirl Boiling Liquid∕Gas Separator under Reduced Gravity

10.1063/1.3115490 ◽

2009 ◽

Author(s):

Ryoji Oinuma ◽

Ngoc Nguyen ◽

Neil Dickes ◽

Richard C. Kurwitz ◽

Frederick R. Best ◽

...

Keyword(s):

Heat Transfer ◽

Reduced Gravity ◽

Heat Transfer Characteristics ◽

Boiling Liquid ◽

Transfer Characteristics ◽

Gas Separator

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Condensation of Steam on Finned Surfaces With Addition of a Surfactant

Heat Transfer: Volume 2 ◽

10.1115/ht2005-72155 ◽

2005 ◽

Author(s):

Andrew T. Morrison ◽

S. M. You

Keyword(s):

Heat Transfer ◽

Surface Energy ◽

Reynolds Numbers ◽

Film Condensation ◽

Vapor Flow ◽

Flow Conditions ◽

Two Phase ◽

Enhancement Of Heat Transfer ◽

Flat Surfaces ◽

Extended Surfaces

A fundamental knowledge of the parameters affecting film condensation is essential for the design of two phase heat exchangers. The current study examines the effect of extended surfaces and surface energy modifications and their interaction for condensation of steam in quiescent and vapor flow conditions. The enhancement of heat transfer for vertical, flat surfaces and two finned surfaces were compared for Reynolds numbers ranging from approximately 10 to 50. The addition of a nonionic surfactant, alcohol alkoxylate, to the system was evaluated for the same surfaces and vapor field conditions. Vapor flow of 0.25 m/s enhanced the heat transfer approximately 40%, while 0.5 m/s vapor velocity produced almost 100% increase in heat transfer. The addition of surfactant to the system produced small enhancement in heat transfer except in the case of condensate hold-up between the fins. In this case, the addition of surfactant increase the heat transfer an additional 25%, likely because the vapor flow and change of surface energy were sufficient to largely eliminate the hold-up of condensate between the fins.

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Convective Heat Transfer From Heated Extended Surfaces With a Confined Slot Jet Impingement

Heat Transfer, Volume 2 ◽

10.1115/imece2004-61442 ◽

2004 ◽

Author(s):

L. K. Liu ◽

M. C. Wu ◽

C. J. Fang ◽

Y. H. Hung

Keyword(s):

Heat Transfer ◽

Experimental Data ◽

Reynolds Number ◽

Mixed Convection ◽

Average Nusselt Number ◽

Jet Impingement ◽

Separation Distance ◽

Nusselt Numbers ◽

Transfer Behavior ◽

Extended Surfaces

A series of experimental investigations with stringent measurement methods on the studies related to mixed convection from the horizontally confined extended surfaces with a slot jet impingement have been successfully conducted. The relevant parameters influencing mixed convection performance due to jet impingement and buoyancy include the Grashof number, ratio of jet separation distance to nozzle width, ratio of extended surfaces height to nozzle width and jet Reynolds number. The range of these parameters studied are Grs = 3.77 × 105 – 1.84 × 106, H/W = 1–10, Hs/W = 0.74–3.40 and Re = 63–1383. In the study, the heat transfer behavior on the extended surfaces with confined slot jet impingement such as the temperature distribution, local and average Nusselt numbers on the extended surfaces has been systematically explored. The results manifest that the effect of steady-state Grashof number on heat transfer behavior such as stagnation, local and average Nusselt number is not significant; while the heat transfer performance increases with decreasing jet separation distance or with increasing extended surface height and jet Reynolds number. Besides, two new correlations of local and average Nusselt numbers in terms of H/W, Hs/W and Re are proposed for the cases of extended surfaces. A satisfactory agreement is achieved between the results predicted by these correlations and the experimental data. Finally, a complete composite correlation of steady-state average Nusselt number for mixed convection due to jet impingement and buoyancy is proposed. The comparison of the predictions evaluated by this correlation with all the present experimental data is made. The maximum and average deviations of the predictions from the experimental data are 7.46% and 2.87%, respectively.

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