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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-474-8

ISBN Online: 978-1-56700-473-1

International Heat Transfer Conference 16
August, 10-15, 2018, Beijing, China

ALUMINUM MICROPOST WICKS WITH A CIRCULAR HYPERBOLOID SHAPE FOR MICRO HEAT SPREADERS

Get access (open in a dialog) DOI: 10.1615/IHTC16.bae.023832
pages 801-807

Abstract

We propose Al micropost evaporator wicks for ultralight micro heat spreader that are fabricated using the wet etching followed by the chemical oxidation techniques. By applying the multi-step etching, we fabricate dense arrays of Al microposts with hyperboloid shape, and the wicks are oxidized to improve the wettability and corrosion resistance with operating fluids including water. The corrosion resistance of the proposed Al evaporator is investigated using the polarization scanning test. Due to oxide barrier, the Al nanostructured wick showed ~80% higher corrosion resistance compared with bare Al wicks. The heat transfer experiments conducted within a well-controlled environmental chamber showed that the proposed Al wicks provide the high heat transfer coefficient (> 6 W/cm2·K) at the moderate heat fluxes (< 70 W/cm2) due to its unique hyperboloidal side wall that can increase the thin evaporative film area. Using the energy minimization algorithm combined with finite element model, we clarified that the proposed wick can provide a higher heat transfer coefficient compared with previous cylindrical micropost wicks by stretching the thin evaporative film area. The present work will help develop ultralight micro heat spreader for mobile electronics and EV/HEVs.