Numerical investigation of forced convection of nanofluids in circular tubes

In this paper developing laminar forced convection flow of a water-gamma Al2O3 nanofluid in a circular tube submitted to a constant and uniform heat flux at the wall is numerically investigated. A single and two-phase model (discrete particles model) is employed with either constant or temperature-dependent properties. The investigation is accomplished for a size particles equal to 100 run. Convective heat transfer coefficient for nanofluids is greater than that of the base liquid. Heat transfer enhancement is increasing with the particle volume concentration but it is accompanied by increasing wall shear stress values. The effect of Reynolds number is greater when properties depend on temperature and for higher concentrations.