Critical Review of Corrugation in Tubular Heat Exchangers: Focus on Thermal and Economical Aspects

Heat exchangers (HXs) are crucial in transmitting thermal energy in various industrial and domestic applications. Efforts to improve the design of HXs over the years have resulted in heat transfer enhancement with the penalty of pressure loss (∆P). Researchers have implemented various methods to enhance heat transfer. These methods have been categorized based on the need for external power. Active heat transfer methods require external energy, whereas passive heat transfer methods operate without an external power source. Increasing the effective surface area for heat transfer or inducing turbulence through surface alterations can improve passive heat transfer, leading to secondary flow. Of all the surface alterations, the corrugated tubes are particularly significant for enhancing the heat transfer in a turbulent flow, as they result in a reasonable increase in ΔP. Apart from an increase in ΔP, the initial cost of corrugated tube HX is higher than that of simple HX. Therefore, one should not write off the economic analysis of any passive enhancement technique. Various applications increasingly use corrugation in systems like the primary and secondary heat transport systems of nuclear reactors, refrigeration, and other industries. This paper critically reviews thermal investigations for improving heat transfer and a comprehensive economic analysis of corrugated tube HXs.