This study investigates the impact of flow profile on heat transfer in nanofluid flow, specifically focusing on the influence of sinusoidal rib shapes and different space ratios (ε/h) ranging from 0 to 1. The research uses Al₂O₃ nanofluid as the working fluid and examines the effects of varying Reynolds numbers (from 5000 to 20,000) and nanoparticle volume fractions (from 0 to 6%). The channel's upper surface is subjected to a uniform heat flux, and the performance of the corrugated surface is analyzed in terms of the mean Nusselt number, coefficient of friction, and Performance Evaluation Criteria (PEC) index. Key findings include: - The highest PEC index is achieved for ribs with a space ratio (ε/h) of 0 at a Reynolds number of 5000 and a volume fraction of 6% nanoparticles. - The average Nusselt number increases with higher particle volume fractions and Reynolds numbers. - The friction factor decreases as the Reynolds number increases for all channel cases. - Ribbed channels with a rib distance of 0 mm (ε/h = 0) produced the highest average Nusselt number for all Reynolds numbers. The study concludes that using sinusoidal micro-channels with nanoparticles is more efficient for enhancing heat transfer compared to using nanoparticles in smooth micro-channels. The results provide valuable insights for optimizing heat transfer in thermal energy systems.This study investigates the impact of flow profile on heat transfer in nanofluid flow, specifically focusing on the influence of sinusoidal rib shapes and different space ratios (ε/h) ranging from 0 to 1. The research uses Al₂O₃ nanofluid as the working fluid and examines the effects of varying Reynolds numbers (from 5000 to 20,000) and nanoparticle volume fractions (from 0 to 6%). The channel's upper surface is subjected to a uniform heat flux, and the performance of the corrugated surface is analyzed in terms of the mean Nusselt number, coefficient of friction, and Performance Evaluation Criteria (PEC) index. Key findings include: - The highest PEC index is achieved for ribs with a space ratio (ε/h) of 0 at a Reynolds number of 5000 and a volume fraction of 6% nanoparticles. - The average Nusselt number increases with higher particle volume fractions and Reynolds numbers. - The friction factor decreases as the Reynolds number increases for all channel cases. - Ribbed channels with a rib distance of 0 mm (ε/h = 0) produced the highest average Nusselt number for all Reynolds numbers. The study concludes that using sinusoidal micro-channels with nanoparticles is more efficient for enhancing heat transfer compared to using nanoparticles in smooth micro-channels. The results provide valuable insights for optimizing heat transfer in thermal energy systems.