Performance evaluation of MEMS heat sinks having straight microchannels integrating rectangular sidewall cavities in in-line pattern
Nedal Omar El-Saeh, Fadi Alnaimat, Bee Teng Chew, Boby Mathew
Abstract
• Straight microchannels with sidewall cavities enhance performance of MEMS heat sinks. • Studies conducted for Reynolds number from 100 to 750. • Thermal resistance of straight microchannels with sidewall cavities lower than straight microchannels. • Pumping power of straight microchannels with sidewall cavities lower than straight microchannels. This work details a silicon-based MEMS heat sink having straight microchannels integrating rectangular sidewall cavities in in-line pattern and employing water for thermal management of microelectronic chips. Simulation-based studies are done for Reynolds number ( Re ) between 100 and 750 and the model is validated. The thermal resistance ( R th,total ) and pumping power ( PP f ), of the proposed MEMS heat sink, are lower than that of the conventional MEMS heat sink. At the largest Re , the R th,total of the proposed MEMS heat sink is only ∼78 % of the R th,total of the conventional MEMS heat sink and PP f of the former is only ∼91 % of the latter. Moreover, the Nusselt number ( Nu ) and Poiseuille number ( Po ) of the straight microchannel integrating rectangular sidewall cavities is higher and lower than that of the straight microchannel, respectively. With the increase in Re , the Nu of the proposed MEMS heat sink in comparison with that of a conventional MEMS heat sink varied from ∼103 % to ∼147 % while the Po of the former in comparison with the latter varied from ∼81 % to ∼91 %. There exists a threshold for the length of the sidewall cavities below which the performance of the proposed MEMS heat sink is not influenced by the same. Above this threshold, increase in length decreases, for a specific Re , both R th,total and PP c as well as increases and decreases the Nu and Po , respectively. Increase in Re leads to reduction of R th,total and increase of Nu with decrease in the width of the sidewall cavities; both PP f and Po increase with increase in Re though the influence of width of sidewall cavities on them is negligible. The increase in the number of sidewall cavities decreases R th,total and PP f while increasing and decreasing the Nu and Po , respectively. The increase in hydraulic diameter decreases both R th,total and PP f while increasing both Nu and Po .