An Inclusive Review on Structural Enhancement Techniques in Forced Condensation Inside Tubes

In this review, different types of enhanced tubes in combination with variation of operating parameters are comprehensively discussed. The study focuses on recent developments of different structures on the inner periphery of tubes which help in development of secondary flow and increased turbulence to enhance heat transfer coefficient. For the comparison, enhancement factors are studied for various tube types and graphical representations are provided for visual inspections. The heat transfers in smooth tube were enhanced with inclinations, and optimum inclination angles for maximum heat transfers were reported. The paper also summarises studies on helical tubes and their corresponding heat transfer enhancements. For inducing turbulence along with increased surface areas, uniform distributions of dimples, pin fins, corrugations, and petal arrays are tried. These enhanced structural tubes were able to perform sometimes even better than micro-fin tubes. Additionally, the ongoing numerical and experimental studies in the current area loading towards development of correlations are briefly explained. The study also identifies various area for improvement and provides guideline for future research to be carried out for enhancement in-tube condensation heat transfer