Computational fluid dynamics analysis in a ribbed tube with different twisted tape inserts to enhance the heat transfer

Abstract

Computational fluid dynamics analysis has been carried out on a ribbed tube with different twisted tape inserts with a uniform heat flux condition to study the performance characteristics of thermal efficiency, friction factor and mean Nusselt number. For treating the working fluid (i.e. air), simulations (Ansys Fluent) were carried out in a turbulent region by choosing a suitable Reynolds number. A ribbed tube with full length twisted tape is tested and compared with short length twisted tapes. To avoid decaying along the tube, half-length twisted tape was introduced to produce a strong swirl flow, whereas in the case of full length twisted tape stronger swirling flow is observed along the complete length of the tube. The numerical results indicate that when compared to half-length twisted tape (i.e. λ = 0.14, 0.27 and 0.36), full length twisted tape show better heat transfer, friction factor and improvement in the enhancement efficiency. It is also observed that numerical results are in good agreement with the experimental and correlated values of the mean Nusselt number in the order of ±10% in the range of Reynolds number 25,000–110,000.

KEYWORDS:

• CFD
• inserts
• Nusselt number
• friction factor and heat transfer rate

Disclosure statement

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