Combined radiative and convective heat transfer to laminar flow in a flat conduit

Heat transfer to laminar fluid flow between parallel plates with combined radiation and convection was solved with an approximate analysis, and the effects of optical thickness, axial distance and the conduction-to-radiation parameter on the Nusselt number were investigated. The accuracy of the solution was checked by applying the present method of solution to the slug flow problem between parallel plates for which an exact solution is available. Results were compared with those obtained by other investigators by purely numerical methods of solution. These comparisons show that the present method is sufficiently accurate when the conduction-radiation interaction is weak. The results are shown to be valid over a larger range of distance from the channel entrance when the conduction-radiation interaction is weak.