3D Simulation on turbulent flow and heat transfer behaviors in a five-start corrugated tube: Effect of depth ratio and tube modification

Abstract

This paper presents a 3D simulation of turbulent flow and heat transfer behaviors in a five-start corrugated tube having depth ratios, DR = 0.02-0.16 and constant pitch ratio, PR = 1.0 0 and the Reynold number ranging from 5000 to 20,000. The effects of modified tubes: five-start vortex-flow corrugated tube and five-start cross corrugated tubes with different PR = 1.0-2.5 and constant DR = 0.06, were investigated. The results show that swirl flows were generated by the five-start corrugated tube with spiral wall while the five-start vortex-flow corrugated tube and five-start cross corrugated tube created a pair of vortex and multiple vortices flows, respectively. The modified tubes provided a heat transfer rates (range 26.8-172.1%) and thermal enhancement factor (range 12.6-90.8%) higher than the five-start corrugated tube. The five-start vortex-flow corrugated tube provided the highest thermal enhancement factor at 2.07 at DR=0.06, PR=1.5 and Re = 5000.

Keywords

• heat transfer
• friction factor
• thermal enhancement factor
• swirl flow
• corrugated tube