Enhanced Thermo-Hydraulic Performance in Heat Exchanger Tube Equipped With Coil Strip Metal Foam Inserts

This article proposes a novel experimental comparison of the thermo-hydraulic of coiled-strip inserts for two types: copper foam coil-strip inserts (CFCSI) made of open-cell copper foam, and coiled-strip inserts (CSI) made of aluminum within a heat-tube in turbulent flow (4000–30,000). The newly designed CFCSI aims to improve the elevated thermal performance factor (TPF) above that of CSI in similar circumstances. The CFCSI and CSI used were with three-pitch lengths of (P = 15, 20, and 25 mm). The interesting detection in the situation of tubes equipped with CFCSI in the novel arrangement was that the secondary vortices' strength manifested a periodic variation from weak to strong lengthwise in the mainstream direction, which introduced a rise in the TPF. Also, the results elucidated that the heat transfer was improved (Nusselt number, Nu) for the CFCSI and CSI models, and this improvement decreases with increasing pitch length, but the CFCSI showed a higher heat transmission rate compared to the CSI and plain tube. The Nu of CFCSI averaged about (432%–384%) compared to the CSI, depending on the pitch length, and about (130%–108%) over that of the clear tube of the CSI. The suggested CFCSI has a TPF of 1.61–1.5 at 4000 Reynolds number (Re) and 15 mm pitch length, which is considered greater than CSI and plain tubes.