Natural Convection Within an Eccentric Annulus at Different Orientations

Abstract

DOI: 10.2514/1.T3938 The purpose of this study is to predict numerically the natural convection within an annulus formed between two horizontal eccentric circular cylinders. The annulus is isothermally heated from its inner cylinder, and the induced flowandthermal fieldsarepredictedatdifferentorientationsoftheannulussymmetryline.Thegoverningequations for induced laminar natural flow within the annulus are solved using the Fourier spectral method. The heat convection process within the annulus is dependent on the Rayleigh number, Prandtl number, outer-to-inner cylinder radius ratio, eccentricity, and angle of inclination of the annulus symmetry line to the horizontal, � . The Prandtl number and radius ratio are fixed at 0.7 and 2.6, respectively. The Rayleigh number is considered up to 10 5 , while the annulus symmetry line orientation is varied from horizontal position (� 0) to vertical position (� 90). TheresultsforlocalandmeanNussultnumbersareobtainedanddiscussedtogetherwiththedetailsofboth flowand thermal fields. The study has predicted the global flow circulation within the annulus in cases of � ≠ 90 . The study