Numerical Study of Three-Dimensional Mixed Convection in an Eccentric Annulus

Mixed convection of air with a Prandtl number of 0.7 in eccentric horizontal annuli is numerically investigated. The inner cylinder is at a higher temperature, while the inner and outer cylinders can be rotated either clockwise or counterclockwise with a constant angular velocity. The effects of various parameters, such as the eccentricity of the annulus and the Rayleigh number, are studied using a three-dimensional model. The Navier–Stokes equations, along with the energy equation, are solved in an orthogonal structured grid of a bipolar coordinate system employing a finite volume method based on the SIMPLE algorithm. Here, both steady and unsteady results are presented in two separate codes. Three-dimensional considerations lead to a complicated flow pattern, whereas Taylor vortices have a major role on heat and flow characteristics. It is shown that the axial component of velocity in some configurations has a considerable value, therefore, flow pattern and heat transfer characteristics change in compar...