Thermo Hydraulic Performance of Double Pipe Heat Exchanger Affected by Triangular and Semi-Circular Protrusion Insert on Twisted Tape

The experimental studies aimed to enhance the rate of heat transfer by the combined effect of semicircular and triangular protrusions on twisted tape inserts, in a double-pipe heat exchanger over the Reynolds number range of 4000 to 18000. The triangular and semi-circular twisted tape insert features, triangular protrusions along the neutral axis and semicircular edges. The tape insert has 8 mm semicircular protrusions and a triangle protrusion ratio of height and width of 1.1. With x denoting the twist length and B denoting the tape width, the twisted tape has a twist ratio of 4.5. Improvements in the friction factor and Nusselt number show that the heat exchanger's pressure losses have dropped and its heat transfer efficiency has increased. When comparing the analysed configurations, the triangular and semi-circular twisted tape protrusion design outperforms the triangular and semi-circular twisted tape cut-out design. Between the experimental triangular semi-circular twisted tape cutout and the Nusselt number in the triangular semi-circular twisted tape protrusion, there is a 6–10% difference. The findings suggest that in the presence of turbulent flows, the redesigned twisted tape can improve heat transfer efficiency. The contribution of protrusion and twisted tape on heat transfer enhancement is individually assessed and it is found that the best value of twisted tape involvement on enhanced heat transfer, The protrusion design outperforms cutout design by an accuracy of 7.15%.