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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.
The convective heat transfer and friction behaviors of turbulent tube flow through a straight tape with double-sided delta wings (TW) have been studied experimentally. In the current work, the TW 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. TW characteristics are (1) TW with forward / backward-wing arrangement, (2) TW with alternate axis (T-WA) -width ratios and (4) wing-pitch ratios.The experimental result reveals that for using the TW, 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 TW 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 f rom 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.