Convective Cooling of an Extrudate

Convective heat transfer about an isothermal, cylindrical extrudate of constant diameter, issuing continuously from an extrusion die, is investigated numerically, using a commercial CFD software package. The hot extrudate is assumed to move vertically downward, thus giving rise to a combined regime of forced and free convection in the surrounding fluid. Prandtl number of 0.707, corresponding to air near standard conditions, is used. It is seen that when extrudate speed is very low, heat transfer decreases as speed is increased. However this trend is reversed at higher extrudate speed. Flow pattern in the ambient fluid, and effects of Rayleigh number on the extrudate’s heat transfer, will also be presented.