Flow and pressure field characteristics in the porous block compact modeling of parallel plate heat sinks

Growing complexity has resulted in an increased computational effort in CFD modeling of electronic systems. To reduce the computational effort, one or several heat sinks can be represented by a compact "porous block" model, with an effective thermal conductivity and pressure loss coefficient. In this study of parallel plate heat sinks in laminar forced convection, a methodology is developed to analytically determine the fluid properties of compact heat sink models that provide acceptable levels of approximation. The results of an extensive set of CFD simulations for a three heat sink channel, covering three distinct heat sink geometries, air velocities from 0.25 m/s to 2 m/s and various spacings between the heat sinks, were used to create and evaluate the effectiveness of compact models. Use of a two term, equivalent loss coefficient-reflecting the linear and quadratic components in the pressure drop of a porous block-has led to good agreement between the detailed numerical and compact model predictions, with compact heat sink pressure drops usually slightly higher (<10%) than detailed heat sink pressure drops.