Numerical study of laminar combined convection heat transfer of Al2O3-water nanofluid flow in a heated annular pipe

Abstract

This study concerns the 3D flow field and heat transfer of Al2O3-water nanofluid, in an annulus. The external pipe is subjected to a uniform heat flux, while the inner cylinder is adiabatic. By using the nanofluid single phase approach and the finite volume method, the numerical simulation is carried out for a fixed radius ratio and solids concentration while the Reynolds and Grashof numbers are varied. Globally, the results show a qualitative similarity with those obtained with a base fluid alone. As expected, the mixed convection Nusselt number becomes more superior to that of the forced convection when the Grashof number is increased. With a fixed Reynolds number, the temperatures undergo a circumstantial variation under the influence of the Gr number with significant azimuthally variation and for the same concentration, temperatures within the nanofluid are strongly influenced by the Re number