Heat Transfer and Pressure Drop in Turbulent Flow through an Eccentric Converging-Diverging Tube with Twisted Tape Inserts


The aim of this study is to investigate the heat transfer and pressure drop characteristics in an Eccentric Converging-Diverging Tube (ECDT) with twisted tape inserts. Experiments were conducted with tape inserts of three different twist ratios. Cold and hot water are used as working fluids in shell and tube sides, respectively. The effect of the twist ratio and other parameters on heat transfer characteristics and pressure drop are considered. The experimental data for the plain tube and (ECDT) without inserts are compared with (ECDT) with twist tape insert. The results show that the twist tape insert has significant effect on the enhancement of heat transfer. The Nusselt numbers for the (ECDT) are found to be 15% to 45% higher than of the plain tube while for the (ECDT) combined with twisted tape insert is found 52% to 280% higher and pressure drop is found 6.8 times the plain tube. Moreover, (ECDT) combined with a twisted tape insert gives higher heat transfer rate and pressure drop than the (ECDT) alone around 23% to 35% and 98% to 125%, respectively.