Second law analysis of heat transfer and fluid flow inside a cylindrical annular space

Abstract

We investigate analytically the First and Second Laws (of thermodynamics) characteristics of fluid flow and heat transfer inside a cylindrical annulus. Inside the annular gap, the relative rotational motion between the inner and outer cylinders induces fluid motion. The net surface heat flux is always equal at the inner and outer cylinders, but it is varied in magnitude. Simplified governing equations in cylindrical coordinates are solved to obtain analytical expressions for dimensionless entropy generation number (N_S), irreversibility distribution ratio (Φ), and Bejan number (Be) as a function of flow governing and geometric parameters. Spatial distributions of local and average entropy generation rate, and heat transfer irreversibility, are presented graphically. The effects of velocity ratio (λ), group parameter $\text{(Br/Ω)}$, and Brinkman number (Br) on the above parameters are tested.