Numerical simulation of nanofluids flow and heat transfer through isosceles triangular channels

Nanofluids are stable suspensions of nanoparticles in conventional heat transfer fluids (base fluids) that exhibit better thermal characteristics compared to those of the base fluids. It is important to clarify various aspects of nanofluids behavior. In order to identify the thermal and hydrodynamic behavior of nanofluids flowing through non-circular ducts, in the present study the laminar flow forced convective heat transfer of Al2O3/water nanofluid thorough channels with isosceles triangle cross section with constant wall heat flux was studied numerically. The effects of nanoparticle concentration, nanofluid flow rate and geometry of channels on the thermal and hydrodynamic behavior of nanofluids were studied. The single-phase model was used in simulations under steady state conditions. Results reveal that the local and average heat transfer coefficients of nanofluids are greater than those of the base fluid. Heat transfer coefficient enhancement of nanofluids increases with increase in nanoparticle concentration and Reynolds number. The local heat transfer coefficient of the base fluid and that of the nanofluids decrease with the axial distance from the channel inlet. Results also indicate that an increase in the apex angle of the channel, decreases the Nusselt number and heat transfer coefficient. The wall friction coefficient decreases with increasing axial distance from the channel inlet and approaches a constant value in the developed region. Friction coefficient and pressure drop decrease by increasing the apex angle of the channels