Efficient Heat Transfer Augmentation in Channels with Semicircle Ribs and Hybrid Al2O3-Cu/Water Nanofluids

Abstract

Global technological advancements drive daily energy consumption, generating additional carbon-induced climate challenges. Modifying process parameters, optimizing design, and employing high-performance working fluids are among the techniques offered by researchers for improving the thermal efficiency of heating and cooling systems. This study investigates the heat transfer enhancement of hybrid “Al2O3-Cu/water” nanofluids flowing in a two-dimensional channel with semicircle ribs. The novelty of this research is in employing semicircle ribs combined with hybrid nanofluids in turbulent flow regimes. A computer modeling approach using a finite volume approach with k-ω shear stress transport turbulence model was used in these simulations. Six cases with varying rib step heights and pitch gaps, with Re numbers ranging from 10,000 to 25,000, were explored for various volume concentrations of hybrid nanofluids Al2O3-Cu/water (0.33%, 0.75%, 1%, and 2%). The simulation results showed that the presence of ribs enhanced the heat transfer in the passage. The Nusselt number increased when the solid volume fraction of “Al2O3-Cu/water” hybrid nanofluids and the Re number increased. The Nu number reached its maximum value at a 2 percent solid volume fraction for a Reynolds number of 25,000. The local pressure coefficient also improved as the Re number and volume concentration of “Al2O3-Cu/water” hybrid nanofluids increased. The creation of recirculation zones after and before each rib was observed in the velocity and temperature contours. A higher number of ribs was also shown to result in a larger number of recirculation zones, increasing the thermal performance.

Critical operating parameters of solar flat plate collectors using CuO nanoparticles of different volume fractions subjected to natural convection

“…Dispersants have a hydrophobic tail and a hydrophilic polar head group. Dispersants reduce surface tension, interfacial tension, and liquid–solid adhesion 17,19,28,30 . Dispersants improve two materials' wettability.…”

“…Dispersants reduce surface tension, interfacial tension, and liquid-solid adhesion. 17,19,28,30 Dispersants improve two materials' wettability. CTAB (1%) is used as a surfactant.…”

“…In another study, Rashidi et al 18 stated that the nanofluids comprising alumina nanoparticles were employed in various thermal devices owing to their remarkable properties, such as good thermal features, relatively high stability, and ease of synthesis. Togun et al 19 investigated the heat transfer development of Al 2 O 3 –Cu/water nanofluids flowing in a two‐dimensional channel with semicircle ribs. Results presented that the existence of ribs improved the heat transfer in the passage.…”