Fully Developed Convective Heat Transfer of Power Law Fluids in a Circular Tube

We present a theoretical analysis for fully developed convective heat transfer in a circular tube for power law fluids by assuming that the thermal diffusivity is a function of temperature gradient. The analytical solution is obtained and the heat transfer behaviour is investigated under a constant heat flux boundary condition. It is shown that the Nusselt number strongly depends on the value of power law index n. The Nusselt number sharply decreases in the range of 00.5, the Nusselt number decreases monotonically with the increasing n, and for n>20, the values of Nusselt number approach a constant.