Validation of models for air cooled plane fin heat sinks used in computer cooling

Plane fin heat sinks, on which a small fan is mounted, are typically used for cooling the CPU in computers. The two most common air-flow configurations are parallel (or duct) flow and impinging flow. A number of analytic, numerical, and semi-empirical models have been published to predict heat sink performance. Most models assume uniform airflow (duct or impinging) at the heat sink inlet. The present work reviews some of the recent and representative models for the two flow configurations. A simple model based on developing laminar flow in rectangular channels is proposed. Experiments were conducted to measure hydraulic and thermal performance of two representative plane fin aluminum heat sinks, one for each flow configuration. The test data are compared with the proposed model for parallel flow and a selected model for impinging flow. A comparison of the proposed duct flow model predictions shows good agreement with the pressure drop and heat transfer data. Similarly good validation of the impinging flow model is established.