Numerical simulation and analytical optimization of microchannel heat sinks

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Tezin Türü: Yüksek Lisans

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Mühendislik Fakültesi, Makina Mühendisliği Bölümü, Türkiye

Tezin Onay Tarihi: 2010

Öğrenci: GÖKER TÜRKAKAR

Danışman: HANİFE TUBA OKUTUCU ÖZYURT

Özet:

This study has two main objectives: The performance evaluation of existing microchannel heat sinks using a CFD model, and the dimensional optimization of various heat sinks by minimizing the total thermal resistance. For the analyses, the geometric modeling is performed using the software GAMBIT while the thermal analysis is performed with FLUENT. The developed model compares very well with those available in the literature. Eight different metal-polymer microchannel heat sinks are analyzed using the model to find out how much heat could be provided to the systems while keeping the substrate temperatures below 85°C under a constant pumping power requirement. Taking the objective function as the total thermal resistance, the optimum geometries have been obtained for the mentioned metal-polymer heat sinks as well as more conventional silicon ones. The results of the optimization code agreed very well with available ones in the literature. In the optimization study, the Intel Core i7-900 Desktop Processor Extreme Edition Series is considered as a reference processor which is reported to dissipate 130 W of heat and to have chip core dimensions of 1.891 cm × 1.44 cm. A dimensional optimization study has been performed for various copper and silicon microchannel heat sinks to cool down this processor. To the best of the author’s knowledge, this study contributes to the literature in that, as opposed to the available analytical microchannel optimization studies considering constant thermophysical properties at the fluid inlet temperature, the properties are evaluated at the area weighted average of the fluid inlet and iteratively calculated outlet temperatures. Moreover, the effects of the thermal and hydrodynamic entrance regions on heat transfer and flow are also investigated.