RADIANT AND CONVECTIVE HEAT-TRANSFER FOR FLOW OF A RADIATION GAS IN A HEATED COOLED TUBE WITH A GRAY WALL

An analytical investigation is presented of the influence of radiative heat transfer on the complex heat exchange problem involving flow of an optically active (radiating) gas inside a tube of diffuse grey properties. The method used is based on Hottel's formulation of zone division, and involves the transformation-zone approach, where radiation gas emission is replaced with an equivalent surface emission. Separable-kernel and surface transformation techniques give a set of non-linear differential equations treated by the Runge-Kutta method with Hamming modification. The solutions are governed by. several independent parameters such as the wall and radiation gas emissivities, inlet and exit gas temperatures, length-diameter ratio of the tube, uniform and non-uniform heat flux and variable convective heat transfer coefficient at the inner surface. The results apply both to heating and cooling situations.