Heat Transfer Enhancement in Tube-in-Tube Heat Exchanger Using Twisted Tape Inserts

This study investigates the enhancement of heat transfer in a tube-in-tube heat exchanger using twisted tape inserts. Twisted tape is a passive technique that induces turbulence and swirl flow, thereby increasing the heat transfer coefficient. The experimental study was conducted on a fabricated copper (inner) and mild steel (outer) heat exchanger operating in both parallel and counter flow configurations. Data were collected for various flow rates with and without twisted tape inserts. Calculations were based on the Log Mean Temperature Difference (LMTD) and Effectiveness-NTU methods. The performance was evaluated in terms of Nusselt number, Reynolds number, heat transfer rate, and effectiveness. Comparative analysis revealed significant improvements in heat transfer with twisted tape, particularly under counter flow. This research presents a comprehensive analysis with supporting literature and simulation data for optimized heat exchanger design.