Numerical study of heat transfer enhancement in twisted clockwise-counterclockwise square ducts

Abstract

The heat transfer and friction factor for the working fluid, such as airflow through a clockwise (CW)-counter clockwise (CCW) square duct, are numerically investigated. The outer cylinder's walls are subjected to a uniform heat flux, and the duct's walls are kept at a constant temperature. For Reynolds numbers of 100–50000, Prandtl numbers of 0.7, 20, and twist ratios of 16.5, 11.5, 7.5, and 2.5, a three-dimensional analysis of fluid flow within the duct area was done. The results of an experiment with a straight square and twisted square duct are compared to the results of this study. The Nusselt number in this investigation is significantly greater than the results of earlier experimental studies. Up to the Reynolds number value of 3000, the percentage rise in Nusselt numbers is similarly indicated as 58–60% greater than the experimental works. Nusselt number and friction factor correlations are also defined.

KEYWORDS:

• Non-circular duct
• twist ratios
• twist clockwise-counter clockwise square duct
• straight square duct
• periodic flow
• twist pitch

Acknowledgments

This work recognised the support of the Mechanical Engineering Department, NIT Durgapur for their valuable advice on the research work and also to provide computational support throughout the study.

Disclosure statement

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