RT Journal Article ID 0064b60008991bf7 A1 Zimparov, Ventsislav D. A1 Penchev, Plamen J. A1 Bergles, Arthur E. T1 Performance Characteristics of Some "Rough Surfaces" with Tube Inserts for Single-Phase Flow JF Journal of Enhanced Heat Transfer JO JEH(T) YR 2006 FD 2006-09-27 VO 13 IS 2 SP 117 OP 137 AB One of the most promising heat transfer enhancement techniques is the compound enhancement method, in which different enhancement techniques are used simultaneously. This study compares the characteristics of some passive combined techniques for single-phase flow studied up to now: rough tube (sand-grain roughness), internally grooved rough tube, three-dimensional internal extended surface, and corrugated tube — all of them combined with twisted-tape inserts. An internally grooved tube with wire coil inserts is also considered. The performance characteristics of these combinations of "rough" surfaces with tube inserts have been assessed using traditional performance evaluation criteria extended by entropy generation. The goal is to evaluate the influence of the characteristic parameters of the tubes: protuberance-height-to-diameter ratio e/Di, relative pitch p/e, relative helix angle (β*, and others, and the relative pitch of the twisted tape or wire coil H/Di on the thermodynamic efficiency. The benefits of replacing the smooth tubes in shell-and-tube heat exchangers were evaluated for different practical applications. The optimal thermodynamic performance can be defined by minimization of the enhancement entropy generation number compared with the relative increase of the heat transfer rate or relative reduction of the heat transfer area. PB Begell House LK https://www.dl.begellhouse.com/journals/4c8f5faa331b09ea,28797bf73339b42e,0064b60008991bf7.html