Critical Conductivity Ratio and Wall Thickness for Conjugate Natural Convection Heat Transfer in Vertical Eccentric Annuli

Abstract

Combined conduction-free convection heat transfer in vertical eccentric annuli is numerically investigated using a finite-difference technique. The effects of geometrical parameters, such as eccentricity and radius ratio, on very practical parameters known as critical values of conductivity ratio above which and wall thickness below which the conjugate effect can be neglected, are presented. Solid-fluid thermal conductivity ratio is varied over a range covering practical cases with commonly encountered wall thicknesses. The obtained results can be of value in many industrial applications. The numerical results show that conjugate effects can be increased or decreased by controlling the geometrical parameters.