Pin-fin heat sink modeling and characterization

Numerical experiments were performed to investigate the turbulent fluid flow and heat transfer from three pin-fin heat sink geometries over the range of Re_D 7,800 to 19,700 with air impingement cooling. The standard k-ε turbulence model was used in predicting the Reynolds stresses. The predictions of junction-to-ambient thermal resistance compare favorably with available experimental results. The analysis presented here illustrates the effect of fin size and channel spacing on the overall distribution of the issuing fluid within the pin-fins. For large finned arrays, much of the impinging air is deflected laterally away from the heat sink. As a result little of the issuing air is allowed to penetrate the inner channels and cool the heat sink. By contrast, for small finned arrays, most of the impinging air flows away from the array via the centerline channels providing very little air for cooling of the inner fins. This situation also reduces the cooling effectiveness