A comprehensive review on compound heat transfer enhancement using passive techniques in a heat exchanger

Abstract

The heat transfer is a very interesting field for efficient, useful, eco-friendly reasons. The economic & environmental factors demand that we get the maximum possible efficiencies from thermal power plants possible only by making more efficient heat exchangers. Increasing the effectiveness of new and existing heat exchangers is a typical criterion of engineers involved with the design of heat exchangers. Augmenting process plant efficiency and finding new ways to reduce energy requirements is always an important design priority. Therefore, the heat transfer augmentation plays a substantial role in improving energy efficiency and development of high-performance thermal systems. The heat transfer augmentation techniques are classified as passive, active and compound techniques. The current article presents an extensive review of experimental and numerical studies on passive compound heat transfer augmentation techniques (PCHTAT), combining two or more of the current techniques can be employed all together to produce an enhancement larger than that produced by using only one augmentation. The compound technique arrangement are (i.e. helical-ribbed tube with double twisted tape inserts, Dimpled tube fitted with a twisted tape swirl generator, non-uniform wire coil, and twisted tape inserts. etc.) which covers the laminar and turbulent flow regions. Interactions between different enhancement methods will increase the overall heat transfer coefficient of the thermal systems than that produced by using only one augmentation technique.