Enhancing thermal performance: a sophisticated analysis of CuO-water nanofluids and twisted tape inserts in tubular heat exchangers-a numerical study

An advanced numerical investigation was conducted on a tubular heat exchanger utilizing CuO-water nanofluid between 0.01% and 0.04% volume fraction to elucidate enhancements in heat transfer rate and effectiveness. The study incorporated twisted tape inserts with three distinct sweeps (5, 10, and 15) for fully developed turbulent flow conditions. The analysis explored varying mass flow rates of the hot nanofluid (0.2–0.5 kg s^-1), while maintaining a constant cold fluid mass flow rate of 0.2 kg s^-1. The k-ε turbulence model was employed to accurately predict heat transfer characteristics in the turbulent regime. Swirl flow analysis revealed a bifurcation of flow patterns: one proximal to the wall and another distal. Results demonstrated a linear correlation between mass flow rate and both heat transfer rate and effectiveness. Peak performance was observed at the highest flow rate, with the maximum effectiveness reaching 0.37 and the heat transfer coefficient attaining 2511 W m^-2 K^-1. This study provides valuable insights into the thermal performance optimization of tubular heat exchangers using nanofluid and twisted tape inserts, offering potential for significant efficiency improvements in heat transfer applications.