Mixed convection heat transfer of nanofluids in a trapezoidal cavity having an adiabatic square body at its center

In this study, the enhancement introduced by nanoparticles is investigated. Nanosized copper particles are dispersed into water which is confined in a cavity with a trapezoidal cross-section. The bottom and top walls of the cavity are adiabatic while the inclined lateral walls are kept at different constant temperatures. The cavity contains an adiabatic block at its center. The top wall of the cavity slides horizontally with a uniform constant velocity. The effect of adiabatic block size and particle volume fraction on the fluid flow and heat transfer is examined. Grashof number is set to 105 whereas Reynolds number is varied to examine the flow and heat transfer for Richardson numbers of 0.1, 1 and 10. The computational results show that heat transfer rate enhances as Richardson number decreases. It is also observed that large size of adiabatic block impedes the fluid circulation which reduces heat transfer rate.