Mixed convection cooling of a microsphere

Fluid flow and mixed (free and forced) convection heat transfer characteristics over a micro-sphere at moderate to high values of both Grashof and Reynolds numbers are numerically investigated at uniform wall temperature boundary condition. Although this topic is crucial in understanding the basic flow and heat transfer features about a miniature sphere, little attention was drawn into it in the open literature. The effects of the engineering parameters such as Reynolds number, Grashof number and Knudsen number, that appears due to fluid slip at the wall, on the velocity and temperature profiles are investigated for both aiding and opposing flows. The range of Knudsen number values used is confined to the flow continuity range (0.001 ≤ Kn ≤0.1) where the Navier-Stokes Equations are used. Therefore, the Knudsen number is assumed small enough to apply a continuum model for the flow field with a temperature jump and frictional slip at the sphere's surface.