Effect of Upstream Viscous Dissipation on Laminar Heat Transfer in Microtubes

The effect of viscous dissipation on heat transfer in microtubes is analyzed. In particular, the effect of upstream viscous dissipation on the entrance temperature distribution and thereby on the downstream temperature field and Nusselt number is analyzed. Heat transfer characteristics of a steady laminar flow of hydrodynamically developed and thermally developing Newtonian fluid are presented. The case of adiabatic upstream preparation of the fluid and uniform wall heat flux condition in the downstream region is considered. The temperature distribution and Nusselt number variation in the thermally developing region of the tube is shown. The heat transfer characteristics are also contrasted with the solution available in literature, which assumes a uniform temperature distribution in the entrance cross section. A case study quantifying the viscous dissipation effect on water flowing through a microtube is presented.