Numerical study of natural convection of a nanofluid in C-shaped enclosures

► Free convection of a nanofluid inside C-shaped enclosures was studied numerically. ► As the C-shaped enclosure becomes narrower, the rate of heat transfer increased. ► The average Nusselt number increased with increase in nanoparticles volume fraction. ► Effect of nanoparticles on enhancement of heat transfer at low Rayleigh numbers is more significant.