Numerical analysis of hybrid nanofluids in rectangular duct for thermal enhancement integrated with polygonal rib

The research was carried out to investigate the augmentation of thermal performances in the Solar Water Heater (SWH) by implementing rough surfaces in the absorber plate and Nanofluid considered a working fluid. A hybrid nanofluid Al2O3 / Cu O (60:40) was taken as a working fluid and compared with Al2O3 nanofluid and base fluid to ascertain the augmentation of convective heat transfer in SWH. The forward and backward trapezoidal shapes of the rib were employed in the absorber plate at relative pitch distances p/e = 10 at relative roughness height e/d = 0.06. Average Nusselt number (Nu), and friction factor (f) were investigated at Reynolds numbers ranging from 4000 to 18000. Turbulent model k-∊ was selected to examine the vortex generated in the fluid flow direction owing to the rough surface. The result reveals that hybrid nanofluid with backward trapezoidal rib at p/e = 10 has produced a higher Nusselt number 95.6 at Reynolds number 18,000 than other ribs and fluid.