Heat transfer and second law analysis of ethylene glycol based ternary hybrid nanofluid under laminar flow
Abstract Experiments were conducted to evaluate the thermal and frictional entropy generation and exergy efficiency of rGO-Fe3O4-TiO2 hybrid nanofluid in a circular tube under laminar flow. The ternary nanoparticles are synthesized using the sol-gel technique and characterized by XRD, SEM, and FTIR. The stable ethylene glycol based ternary hybrid nanofluid were prepared and thermo-physical properties, heat transfer, friction factor, and pumping power at various particle weight concentrations (0.05% to 0.2%) and Reynolds number (211 to 2200) were investigated. Enhancement in the thermal conductivity and viscosity of 10.6% and 108.3% at ψ = 0.2% and at 60°C over the base fluid were obtained. Similarly, Nusselt number is enhanced to 17.78%; heat transfer coefficient is enhanced to 24.76%; thermal entropy generation is reduced to 19.85%; exergy efficiency enhancement of 6.23% at ψ = 0.2% and at Re = 1548 is achieved. The pressure drop, pumping power, and friction factor is augmented to 13.65%, 11.33%, and 16% at ψ = 0.2% and at Re = 221.1 over the base fluid. The overall thermal performance of the system is enhanced to 14.32%. New equations are modeled to evaluate the thermo-physical properties, Nusselt number, and friction factor.