Investigation of Drag Reduction and Heat Transfer in Circular Tube Heat Exchanger with Guar Gum, Gum Arabic and their Copolymer

This study investigates the impact of natural biopolymers on drag reduction and heat transfer enhancement in flowing fluids. Conventional heat transfer fluids, such as water, have limited thermal performance and require higher pumping energy. Synthetic polymers can improve performance but often raise environmental concerns. Therefore, this work assesses eco-friendly biopolymers. Gum Arabic (GA) and guar gum (GG) are examined to determine their potential as sustainable additives. Experiments were carried out in a closed cylindrical flow system. Polymer solutions were prepared at concentrations of 50, 100, 200, and 250 ppm, with the temperature held constant at 30 °C. Thermophysical properties such as density, viscosity, and thermal conductivity were measured. Heat transfer coefficient and drag reduction were assessed at various flow velocities for GA, GG, and their mixtures. Results demonstrate that polymer additives significantly enhance thermal performance compared with distilled water. At a velocity of 3.6 m/s, GA reached the highest heat transfer coefficient of 17,002 W/m²K, representing a 29.84% increase over water. Polymer mixtures also improved heat transfer. GA75:GG25 and GA50:GG50 increased heat transfer by 9.83% and 7.89%, respectively. Conversely, GG showed the highest drag reduction of 24.92%, while GA50:GG50 and GA75:GG25 achieved 19.86% and 12.61% drag. This study concludes that a natural biopolymer mixture can simultaneously improve heat transfer and decrease drag at very low concentrations (≤250 ppm), providing a sustainable alternative to synthetic polymer additives.