Simulating of heat transfer enhancement via a water-based nanofluid in enclosures with curved side walls

This paper deals with heat transfer and fluid flow of natural convection in enclosures (square enclosure and enclosures with concave/convex walls) filled with water based Cu, and subjected to a constant imposed wall temperature. The governing equations of momentum and energy are formulated using the dimensionless form of transport equations in bipolar coordinates for a laminar two-dimensional incompressible and Newtonian flow which is expressed in terms of stream-function, vorticity and temperature. The resulting equations are numerically solved using the finite volume method (FVM) implemented in an in house-built computer code. The key parameters governing the problem are the Rayleigh number up to 10(5), the Prandtl number of 6.2 and nanoparticles' volume fraction from 0 to 0.2. The relevant results are presented in terms of isotherms and streamlines. It is found that the heat transfer increases with nanoparticles' volume fraction for the entire range of Rayleigh number considered. Besides this, heat transfer in the square enclosure remains better than for the other enclosures with curved walls.