FREE-CONVECTION LIMITS FOR PIN-FIN COOLING

An analytical solution for a system consisting of a pin-fin heat sink and a chimney is presented. The result is applied to problems in which the size of the overall system is constrained. For a given heat dissi pation and total system size, optimal values of the pin-fin diameter a nd heat-sink porosity are observed. The optima occur for systems with and without chimneys. The optimization is used to show that the minimu m thermal resistance from a pin-fin heat sink is about two times large r than that of an idealized model based on inviscid flow.