Experimental study of turbulent forced convection heat transfer and friction factor in dimpled plate heat exchanger

Highlights: • Heat transfer studies of nanofluid in dimple plate heat exchanger are performed. • Heat transfer rate rises with increase in mass flow rate and concentration. • Overall heat transfer coefficient increases by 89% at 0.3%w/w nanofluid. -- Abstract: In this work, heat transfer behaviour of γ-Al₂O₃/water nanofluid in turbulent flow condition in a dimple plate heat exchanger is investigated. The effects of flow rates of hot and cold fluids for different concentrations (0.1, 0.2 and 0.3%w/w) of suspended nanoparticles on the heat characteristics and effect of enhancement by the addition of nanoparticles to base fluid are also examined. The comparison of the heat transfer behavior of nanofluid with that of the base fluid (water) resulted in heat transfer augmentation with an increase in the concentration of the nanoparticle. The γ-Al₂O₃/water nanofluid possesses better heat transfer performance than the base fluid at higher nanoparticle concentrations. The studies on pressure drop are also investigated to determine the friction factor of the fluid in the Reynolds number range. Nusselt number correlations are developed for the working fluids for evaluation of heat transfer coefficient.