Natural Convection Within an Eccentric Annulus at Different Orientations

作者：Mahfouz F M^*

来源：Journal of Thermophysics and Heat Transfer, 2012, 26(4): 665-672.

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 flow and thermal fields are predicted at different orientations of the annulus symmetry line. The governing equations 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, lambda. The Prandtl number and radius ratio are fixed at 0.7 and 2.6, respectively. The Rayleigh number is considered up to 105, while the annulus symmetry line orientation is varied from horizontal position (lambda = 0) to vertical position (lambda = 90). The results for local and mean Nussult numbers are obtained and discussed together with the details of both flow and thermal fields. The study has predicted the global flow circulation within the annulus in cases of lambda not equal 90. The study has also shown that, for a given value of Rayleigh number as lambda increases, the steady mean Nusselt number increases for negative eccentricities, whereas it deceases for same but positive eccentricities.

• 出版日期2012-12