Prediction of thermal performance degradation of air-cooled fine-pitch fin array heat sinks due to fouling

The fouling of air-cooled fine-pitch heat sinks by air born dust particles has become a major reliability concern for desktop and notebook personal computers, where significant thermal performance degradation can result. This paper investigates for the first time heat sink fouling mechanisms by both analytical and experimental analyses. The contribution of two fouling modes, namely accumulation of a thermally insulative dust coating on the fins within the heat sink channels, and blockage of the heat sink leading edge entrance, is quantified. It is found that the former fouling mode does not significantly increase heat sink thermal resistance. Instead, heat sink thermal performance degradation is essentially attributable to leading edge entrance blockage, which reduces the airflow rate through the heat sink by increasing pressure drop