An inclusive review on structural enhancement techniques in forced condensation inside tubes

Present review is a comprehensive approach to document and understand the role of surface structures in delivering the enhanced thermal–hydraulic performance during in-tube condensation. The present study classifies works of literature based on their primary objective of study: tube type, size, refrigerant, flow pattern, and operating conditions. The heat transfer and pressure drop observed in experimental literature are analysed and optimum conditions are reported by highlighting the physics behind them. Some experimental results are also included to observe the effect of operating parameters on condensation heat transfer characteristics. The influence of enhanced structures on flow regime is also mentioned wherever reported, as these play an important role on the performance of in-tube condensation. Recent studies on forced convection condensation inside enhanced structured tubes are tabulated to give a brief overview of the ongoing research in the field. A graphical comparison of these tubes based on the results of the experimental studies is also presented to appreciate the condensation performance enhancements achieved through surface structures.