The optimum double diffusive natural convection heat transfer in H-Shaped cavity with a baffle inside and a corrugated wall

Abstract

Double diffusive natural convection (DDNC) is caused by temperature and concentration gradients in buoyancy-driven flows which is applicable in printing, HVAC, and solar collectors. A numerical study is accomplished to investigate DDNC of a hybrid Cu–Al2O3-water nanoliquid inside an H-shaped cavity with a baffle at the top wall. The Finite Element technique and Boussinesq approximation with no slip wall condition are applied to solve the governing equations. The left and right walls are at the cold temperature, while the inner up and down ribs and baffle are at constant heat flux, and other walls are insulated. The effect of Rayleigh number (104-106), Lewis number (2–8), and Buoyancy ratio (1–3) on Nusselt, Sherwood numbers, and entropy generation is investigated. Besides, the effects of baffle inclination angle (−60°to 60°) and also the aspect ratio of the corrugated bottom rib (0.375, 0.75, 1.5) on the mean Sherwood and Nusselt numbers are investigated to find the optimum geometry with the highest heat transfer performance. The results depict that the geometry with baffle angle −60°and with no corrugation has the best Nuavg; however, the geometry with baffle angle +60° and with no corrugation has the best Shavg.

Keywords

• Double diffusive hybrid nanofluid natural convection
• H-shaped cavity
• Nusselt number
• Sherwood number
• Corrugated wall
• Baffle