Performance evaluation of deep spirally corrugated tubes for shell-and-tube heat exchangers

Extended performance evaluation criteria have been used to assess the benefit of replacing the smooth tubes with deep corrugated tubes in shell-and-tube heat exchangers. The goal is to assess the influence of characteristic parameters of the corrugated tubes: height-to-diameter ratio e/D-i, relative pitch p/e, and relative helix angle beta(*) on the thermodynamic efficiency in the case of condensers with steam condensing on the outside of the vertically or horizontally mounted tubes and water in forced convection (non-boiling) flow through the tubes. The geometrical parameters of the tubes studied were in the range of e/D-i = 0.05divided by0.10, p/e = 5.4divided by13.9, and beta(*) = 0.33divided by0.63 for vertically mounted tubes and e/D-i = 0.05divided by0.07; p/e = 4.6divided by18.2 and beta(*) = 0.40divided by0.94 for horizontally established tubes. The thermodynamic optimum can be defined by the minimizing the entropy generation number compared with the relative increase of the heat transfer rate or relative reduction of the heat transfer area.