Paper Title
Thermal Performance Intensification of a Circular Tube Integrated with Torus Rings

Abstract
The heat exchanger plays a vital role in a wide range of industrial applications. The thermal resistance at the solid-fluid interface provides major hindrance for high heat transfer rate. Vortex flow is found to be effective in reducing this thermal resistance and thus several vortex flow devices have been employed to improve the heat exchanger performance. The present work deals with the effect of torus ring inserts on flow and thermal behaviors in a tube subject to a constant heat flux. ANSYS Fluent software is used to perform all the simulations. The fluid flow and heat transfer and are examined over the Reynolds number ranging from 3500 to 17500. The torus rings with aspect ratio of 5 and torus ring inclination from 35 - 75° are investigated and the results are presented for the Nusselt number, friction factor, and thermal enhancement factor. The torus rings generate a pair of vortices along the test tube, which promotes the chaotic fluid mixing and forms a thin boundary layer leading to high heat transfer rate. The streamlines, turbulent kinetic energy, velocity, and temperature fields are examined to explain the mechanism of heat transfer and friction penalty. The performance comparison of the present torus rings with the previously investigated conventional circular and elliptical disks and other vortex flow devices is also provided. Keywords - Thermal Resistance, Nusselt Number, Turbulent Kinetic Energy