Forced convection heat transfer from a particle at small and large Peclet numbers

We theoretically study the forced convection heat transfer from a single particle in uniform laminar flows. We consider asymptotic limits of small and large Peclet numbers Pe. For Pe<<1 (diffusion-dominated regime) and constant heat flux boundary condition on the surface of the particle, we derive a closed-form expression for the heat transfer coefficient that is valid for arbitrary particle shape and flow Reynolds number. Remarkably, our formula for the average Nusselt number Nu is identical to the one obtained by Brenner for a uniform temperature boundary condition (Chem. Eng. Sci., vol. 18, 1963, pp. 109-122). We also present a framework for calculating the average Nu of axisymmetric and two-dimensional objects with a constant heat flux surface condition in the limits of Pe>>1 and small or moderate Reynolds numbers. Specific results are obtained for the heat transfer from spheroidal particles in Stokes flow.