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

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.