Influence of twisted tape length on the thermal performance of a heat exchanger tube.

The application of twisted tape inserts in heat exchangers allows higher heat transfer rates with a simultaneous loss of energy due to turbulence and friction. In a conventional approach, the twisted tape is placed in the entire length of the heat exchanger. The present study explores the effect of the length of the twisted tape insert at a different twist ratio (TR) for 4700 < Re < 22,800. The insert length ratio (LR) ranges from 0.25 to 1 and the TR ranges from 1.5 to 6. The maximum Nusselt number corresponds to the LR of 0.75 at a TR of 1.5. The maximum thermo-hydraulic performance is found to be 3.2 for the LR of 0.75 at a TR of 1.5. [ABSTRACT FROM AUTHOR]