Analysis of entropy generation inside concentric cylindrical annuli with relative rotation

摘要

The present article investigates analytically the First and Second Laws (of Thermodynamics) characteristics of fluid flow and heat transfer inside a cylindrical annulus. A relative rotational motion presents between the inner and the outer cylinders which induces the flow. Two different cases are considered: (a) both cylinders are isothermal and kept at different temperatures and (b) the outer cylinder is isoflux and the inner is isothermal. Governing equations in cylindrical coordinates are simplified and solved to obtain analytical expressions for dimensionless entropy generation number (N{sub}S), irreversibility distribution ratio (φ), and the Bejan number (Be) as a function of flow governing and geometric parameters. Spatial distribution of velocity and temperature, volumetric and average entropy generation rate, and heat transfer irreversibility are presented graphically. The effect of velocity ratio (A), the group parameter (Br/Ω), and the Brinkman number (Br) on the above parameters are tested.