Fouling and its mitigation in silicon microchannels used for IC chip cooling

Particulate fouling studies with alumina dispersions in water were performed in rectangular, silicon microchannels having hydraulic diameters between 220 and 225 lm with Reynolds numbers of 17–41. Data show for the most part the absence of particle deposition within the microchannels. The primary reason for this is the relatively high wall shear stress at the microchannel walls of 2.3–3.5 Pa compared to conventional size passageways. In contrast, the headers for the microchannels are quite susceptible to particulate fouling under the same conditions. This is because the shear stress in the header region is lower. Proper adjustment of pH has been identified to effectively mitigate the fouling by controlling the electrostatic forces of repulsion between particle–particle interactions.