Augmentation of thermohydraulic performance in a dimpled tube using ternary hybrid nanofluid

Abstract

This computational study explores the thermal and hydraulic efficiency of heat exchanger tube configurations utilizing hybrid nanofluids and circular dimples. Seven distinct configurations incorporating different volumetric concentrations of three nanoparticles (GnP, MWCNT, and Fe3O4) and two circular dimple pitch ratios are examined. The investigation concentrates on crucial parameters, including Nusselt number, friction factor, and thermohydraulic performance. The numerical analysis specifically addresses single-phase flow within the Reynolds number range of 5000-30000, maintaining a constant surface heat flux during simulations. Notably, Nusselt number consistently rises with Reynolds number across all configurations. Friction factor analysis indicates minimal sensitivity to hybrid nanofluid ratios but an increase with circular dimples. Despite the elevated pressure drop, the thermohydraulic coefficient consistently surpasses 1, signifying a net energy gain from enhanced heat transfer. Optimal performance is observed in the S5-P/Dt=1 configuration, exhibiting the highest thermohydraulic coefficient at 1.35, while the P/Dt =2 variation within the same fluid model presents a slightly lower value of 1.32.