Enhancement Heat Transfer in a Tube Fitted with Passive Technique as Twisted Tape Insert - A Comprehensive Review

The process of improving heat transfer is one of the important topics that are constantly studied. There are three techniques to improve the heat transfer (passive, active and compound). Most studies are done using the passive technique because it does not need external energy. its work is only to mix the flow to control the growth of the boundary layer and to increase the thermal exchange between the wall and the fluid flow by placing the techniques inside the flow. In this study, emphasis was placed on the studies and research carried out on the first technique (passive technique) and put in a table according to the years of publication as a reference for the students studying in this subject and for heat exchangers designers who aim to reduce weight and cost in the process of manufacturing heat exchangers for reduce their effort and time to reach the optimal design and get the best results