Numerical simulation of laminar forced convection heat transfer of Al2O3–water nanofluid in a pipe with return bend

Abstract

Laminar forced convection heat transfer of the Al2O3–water nanofluid in a pipe with a return bend is analyzed by using a finite element method. The results show that the average Nusselt number increases with increasing Reynolds number and Prandtl number, and the increment of specific heat in the nanofluid contributes to the heat transfer enhancement. The average Nusselt number in the return bend appears higher than that in the inlet and outlet pipes due to the secondary flows. However, the pressure drop in the pipe largely increases with the increment of nanoparticle volume concentration. The empirical correlations for the average Nusselt numbers are obtained as functions of the Dean number and the Prandtl number.