Effects of nanoparticles mean diameter on the particle migration and thermo-hydraulic behavior of laminar mixed convection of a nanofluid in an inclined tube

Laminar mixed convection of a nanofluid consisting of Al2O3 and water through an inclined tube has been investigated numerically. As mathematical model two-phase mixture model has been adopted, thus three dimensional elliptical governing equations have been solved to understand the flow behavior at different Re-Gr combinations. Control volume technique is used for discretization of the governing equations. For the convective and diffusive terms the second order upwind method was used while the SIMPLEC procedure was adopted for the velocity-pressure coupling. For different nanoparticle mean diameters and tube inclinations thermo-fluid parameters such as secondary flow, axial velocity profiles, nanoparticles distribution at the tube cross section, axial evolution of peripheral average convective heat transfer coefficient and pressure drop along the tube, have been presented and discussed. Maximum enhancement on the heat transfer coefficient is seen at tube inclination of 45A degrees.