Enhancing boiling heat transfer for electronics cooling by embedding an array of microgrooves into sandblasted surfaces

The present study proposed some compound surfaces having multi-dimensional enhancement mechanism (earlier boiling initiation, effi cient and extended limit of heat transfer) by incorporating microgrooves into the rough sandblasted surfaces. By embedding an array of microgrooved lines (370 μm wide and 300 μm deep) into aluminum substrate, substantial augmentation in pool boiling of a highly wett ing liquid (dielectric fluid, HFE-7200) is achieved. Replacing 14% and 22% of the sandblasted surface with microgrooves results in a more than 13 times and 19 times increase in heat transfer at a wall superheat of 10oC when compared to a smooth polished surface. This is because these microsized grooves help to trap more liquid volume. Consequently, the boiling is initiated at relatively low wall superheats. To understand the performance and mechanisms underlying this substantial enhancement, the compound surfaces are further compared with intrinsic (machined), and sandblasted surfaces under saturated nucleate pool boiling of dielectric liquids through scanning electron microscopy (SEM) and high-speed imaging. The use of compound fabrication represents a potential approach to fabricate highly effi cient and high heat flux boiling surface for the dielectric and other highly wetting liquids.