Natural Convection Heat Transfer between Two Concentric and Eccentric Oblate Hemi Spheroids with Different Elliptical Ratios.

Document Type : Research Studies

Author

Mechanical Power Engineering Department., Faculty of Industrial Education., Suez Canal University., Suez., Egypt., 43515., Suez.

Abstract

In this paper, !.he natural convection heal transfer between a pair of concentric and eccentric  oblate hemi-spheroids with different elliptical ratios was: depicted experimentally and  numerically. Four pairs of oblate hemi-spheroids having elliptical ratios of 0.0, 0.25, 0.5, 075  and 3 diameter ratio of 2 for each pair were cut using the wire-cut JSEDM CNC machining.  The inner hemi-spheroid was heated while the outer one was exposed to the room temperature.  The experimental tests SC3Jl the effect of the orientation modes (horizontal, inclined, ver1ical  inclined revolved and vertical revolved) on the natural- convection heat transfer between the  inner and outer surfaces of cach pair. A mathematical model was devoted for the case study to  investigate the effect of the eccentricity on the thermal performance of such cases. The model,  was solved numerically using FLUENT CFD solver. The CFD result, were validated via  corresponding experimental data. The temperature and velocity contours of the air gab were  displayed to indicate the ring movement of the buoyancy driven air plume. The comparison  among the results of the present attempt and those by the literature implied that; a notable  Increase in the natural convection heat transfer rates could be satisfied through the gabs among  successive layers of hemi-spheroids having higher elliptical ratio rather than the hemi-spheroids  ones. Also, the positive vertical eccentricity shows remarked increase in natural convection heat  transfer rates rather than both concentric; and negative eccentric cases.  

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MEJ- Mansoura Engineering Journal
Volume 33, Issue 4
December 2008
Pages 69-85

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