A study on heat transfer enhancement using straight and twisted internal fin inserts

The present study investigated the effect of internal aluminum fins with a star-shape cross-section on the heat transfer enhancement and pressure drop in a counterflow heat exchanger. A concentric-tube heat exchanger was used with water as the working fluid. The heat transfer rate increased by 12–51% over a plain tube value, depending on internal fin configurations used. However, the pressure drop also increased substantially by 286–399%. The results showed that a straight-fin configuration is the best to produce a heat transfer increase in a counterflow heat exchanger. Twisted fin configurations did not further increase the heat transfer rate.