Improving heat transfer efficiency in a ribbed channel with two test sections using hybrid nanofluid

Abstract

Improving the rate of heat transfer is a key factor in making thermal devices for various industries more efficient and less energy consuming. With the development of corrugated channels that improve convection in an affordable way, passive techniques to optimize heat transfer have come to market. The objective of this study was to evaluate the performance of a new geometric design of a corrugated channel and the effect of hybrid nanofluids (Ag-ZnO/water, Ag-TiO₂/water, Ag-Al₂O₃/water and Ag-MgO/water) with different volume concentrations on heat transfer enhancement. The results show that the new geometry of the corrugated channel increases the Nusselt number and the Performance Evaluation Criterion by 94 % and 13,73 % respectively compared to the smooth channel and by 10,31 % compared to the previously studied ribbed channel. The increase the Reynolds number improves the heat transfer due to higher flow velocities and rib disturbance. However, the presence of ribs results in higher friction factors and pressure drop compared to smooth channels, which we have attempted to reduce by up to 14 % by increasing the rib width. The introduction of Ag (0.5 %)-TiO₂(1.5 %)/water hybrid nanofluid increases heat transfer by 16.75 % compared to water. In addition, the use of Syltherm 800 as the base fluid increases the heat transfer enhancement to a good level. These results contribute to understanding the effects of rib distribution over two test sections, rib width and nanoparticle volume fraction in hybrid nanofluids on ribbed channel performance. They also help to optimize the design of efficient heat transfer systems.