A study of the effect of triangular and rectangular surface waves on the natural convective heat transfer from a circular upward facing heated horizontal isothermal surface

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dc.contributor.author Oosthuizen, Patrick H. en
dc.date.accessioned 2017-09-19T12:48:18Z
dc.date.available 2017-09-19T12:48:18Z
dc.date.issued 2017 en
dc.description Papers presented at the 13th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Portoroz, Slovenia on 17-19 July 2017 . en
dc.description.abstract Natural convective heat transfer from a horizontal, upward facing circular isothermal heated surface imbedded in a large flat adiabatic surface has been numerically studied. The heated circular surface is covered with a series of waves which are arranged in an axially-symmetric (concentric) manner around the vertical axis of the horizontal circular surface. Surface waves with a triangular cross-sectional shape and with a rectangular cross-sectional shape have been considered. Conditions under which the flow is laminar, transitional, and turbulent have been considered. The flow has been assumed to be axially-symmetric and steady. Fluid properties have been assumed constant except for the density change with temperature that gives rise to the buoyancy forces which has been treated using the Boussinesq approach. The commercial CFD solver ANSYS FLUENT© was used to obtain the numerical solutions. The standard k-epsilon turbulence model was employed with full account being taken of buoyancy force effects. The heat transfer rate from the heated surface expressed in terms of the Nusselt number is dependent on the Rayleigh number, the number of surface waves, the shape of the surface waves, the dimensionless height of the surface waves, and the Prandtl number. Results have only been obtained for the case where there are five surface waves and for a Prandtl number of 0.74. A detailed study of the variation of the Nusselt number with Rayleigh number for various dimensionless surface wave heights has been undertaken. The heat transfer rates for the wavy surface have been compared with those which would exist in the case of a non-wavy (wave height of zero) surface. en
dc.description.sponsorship International centre for heat and mass transfer. en
dc.description.sponsorship American society of thermal and fluids engineers. en
dc.format.extent 6 pages en
dc.format.medium PDF en
dc.identifier.uri http://hdl.handle.net/2263/62325
dc.language.iso en en
dc.publisher HEFAT en
dc.rights University of Pretoria en
dc.subject Natural convective heat transfer en
dc.subject Isothermal surface en
dc.subject Triangualar and rectangular surface waves en
dc.title A study of the effect of triangular and rectangular surface waves on the natural convective heat transfer from a circular upward facing heated horizontal isothermal surface en
dc.type Presentation en


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