Numerical investigation and experimental validation of shape and position optimisation of a static wavy flag for heat transfer enhancement

Abstract

This work demonstrates the effect of different shapes and positions of a wavy flag vortex generator on the heat transfer in a rectangular channel using Computational Fluid Dynamics (CFD) analysis. It covers the shape optimisation as well as the position optimisation of the shape optimised flag to achieve the best heat transfer enhancement. The result of post analysis shows that the shape optimised flag is the combination of rectangular and triangular flag and the optimised position is the flags arranged horizontally along the breadth of the channel. Average Nusselt number in the shape optimised flag is 20.5%, 20.88% and 21.35% higher whereas in best optimised position in which 3 shape optimised flags are used it is 63.18%, 67.87% and 73.03% higher than that of no flag condition for Re 8236, 12354 and 18344, respectively. This work also covers the experimental validation for the result of position optimisation. Heat transfer enhancement by introducing additional turbulence have been widely studied, but the use of flag, the effect of different shapes of flag and the flag positions for improving the heat transfer have not been explored much in practical applications. This paper thus presents the use of flag for heat transfer enhancement.

KEYWORDS:

• Convective heat transfer
• heat transfer enhancement
• turbulence
• vortex generator

Acknowledgements

With a firm belief that a guide in a project is the one who holds the candle in the maze of darkness, we take this opportunity to express our profound gratitude to our esteemed guide S M Gaikwad, Asst. Professor, Department of Mechanical Engineering, Army Institute of Technology, Pune. We would also like to thank all our friends and well-wishers without their whole-hearted cooperation and constant encouragement this paper would not have reached to the present shape.

Disclosure statement

No potential conflict of interest was reported by the author(s).