Use of shell conduction plates for compact models of extruded heat sinks in forced convection environments

Shell conduction plates (thin conducting plates) are computational fluid dynamics (CFD) objects that may be used to model three-dimensional conduction in thin, plate-like objects used in electronic cooling applications. The use of zero thickness conducting plates for fins of extruded heat sinks can result in significant reduction in mesh elements when compared to an equivalent case using thick fins. Shell conduction plates model three dimensional conduction in a solid as well as viscous stresses at a fin surface accurately. However, they do not account for the flow impedance caused by the thickness of the actual plates. Therefore, volumetric resistances with appropriate flow loss coefficients derived from existing channel flow correlations were used to account for the flow blockage caused by the fins. The validity of using such a hybrid approach to model extruded heat sinks was studied using Icepak, a CFD software for electronics cooling applications. Results suggest that the present approach can be used to reduce the cost of computational analysis while maintaining accuracy. The above approach resulted in savings in CPU requirements by a factor of approximately 4 to 5. For the cases considered, the grid sizes were reduced by approximately 60%.