The convective heat transfer and friction behaviors of turbulent tube flow through a straight tape with double-sided delta wings(T-W)have been studied experimentally.In the current work

the T-W formed on the tape was used as vortex generators for enhancing the heat transfer coefficient by breakdown of thermal boundary layer and by mixing of fluid flow in tubes.The T-W characteristics are(1)T-W with forward/backward-wing arrangement

(2)T-W with alternate axis(T-WA)

(3)three wing-width ratios and(4)wing-pitch ratios.The experimental result reveals that for using the T-W

the increases in the mean Nusselt number(

Nu

)and friction factor are

respectively

up to 165% and 14.8 times of the plain tube and the maximum thermal performance factor is 1.19.It is also obvious that the T-W with forward-wing gives higher heat transfer rate than one with backward-wing around 7%. The present investigation also shows that the heat transfer rate and friction factor obtained from the T-WA is higher than that from the T-W.In addition

the flow pattern and temperature fields in the T-W tube with both backward and forward wings were also examined numerically.