Efficacy of injectable rib height on the heat transfer and entropy generation in the microchannel by affecting slip flow

In this study, entropy generation analysis and forced convection heat transfer of Al2O3/water in the rectangular microchannel equipped with three injections were examined. The upper wall of the microchannel has a constant temperature while the lower wall is insulated. To improve heat transfer, the injection is performed through variable height ribs. The main objective is to investigate the effect of the height of injectable ribs on heat transfer, pressure drop, and entropy generation. Input variables include rib's height, Reynolds, and nanofluid volume fraction, while output variables are heat transfer, pressure drop, and entropy generation. The results showed that the higher the ribs height, the more heat transfer. The presence of injectable ribs results in a 46.4% enhancement in heat transfer, which, in turn, intensifies the pressure drop and the entropy generation by 234% and 45.3%, respectively. The effects of all input parameters on total entropy generation were also investigated. Finally, analysis of variance (ANOVA) methodology was used to examine the regression model reasonableness between the independent variables and the output variables. Using regression technique, three correlations were acquired for estimating average Nusselt, pressure drop, and entropy generation.