A REVIEW OF FLOW BOILING HEAT-TRANSFER WITH TWISTED TAPE INSERTS

This report reviews experimental investigations of in-tube flow boilin g enhancement using twisted tape inserts. Special aspects of the exper imental methods used in these studies are described in detail, and the general trends observed in the results are presented. Methods of math ematically characterizing the geometric parameters associated with swi rl Bow are introduced, and the theoretical relationships between swirl Bow and axial Row boiling are described. Previously proposed empirica l and semi-empirical predictive methods are presented for heat transfe r and pressure drop with twisted tape inserts in various convective bo iling regimes. These existing correlations are compared, and recommend ations are made regarding experimental methods, design practices, and the use of existing predictive methods.