Experimental investigation of natural convection heat transfer between two oblate concentric and eccentric hemi-spheroids with different elliptical ratios

摘要

In this paper, natural convection between a pair of oblate hemi-spheroids with different elliptical ratios was depicted experimentally. The experimental tests study the effects of the orientation modes (horizontal, inclined, vertical, inclined revolved and vertical revolved) as well as the vertical eccentricity on the natural convection between each pair. Correlations among Nusselt number, Rayleigh number, elliptical ratio and eccentricity were deduced. A notable increase in the natural convection could be satisfied through the gaps among successive layers of hemi-spheroids having higher elliptical ratio rather than hemispherical ones. The positive vertical eccentricity shows remarked increase in natural convection rather than both concentric and negative eccentric cases. Also, the inclination of the minor axis of hemi-spheroids while keeping the major axis parallel to the horizontal plane produces a stronger upward plume rather than different inclination modes.