Abo Bibliothek: Guest

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

EFFECT OF WETTABILITY ON SOLID-LIQUID INTERFACIAL RESISTANCE IN MICROCHANNEL FLOW

Get access (open in a dialog) DOI: 10.1615/IHTC16.nmt.023856
pages 7283-7288

Abstrakt

Although microchannel cooling technology attracts much attention, disagreement between the previous studies and the classical theoretical predictions has not been clarified yet. Nagayama et al. (2017) found that the deviation from classical theory with the reduction of the hydraulic diameters is due to the broken down of the continuum solid–liquid boundary condition in microchannels. Since surface wettability is one of the important factors at solid–liquid interface, the effects of surface wettability on interfacial resistance were focused on in this study. We conducted the experiments of forced convection for single phase laminar flow in a parallel-plate microchannel. Si microchannels with different surface wettability and hydraulic diameter were under investigation. Three kinds of surfaces were prepared: (1) super-hydrophilic surface treated by a solution of sulfuric acid and hydrogen peroxide (contact angle 0 degree), (2) hydrophilic surface covered by SiO2 thin film (contact angle 30 degree) and (3) hydrophobic surface fabricated by anodic etching (contact angle 108 degree). It is found that the thermal slip length (i.e. thermal resistance) increases with increasing contact angle, e.g. approximately 80?m at the super-hydrophilic surface and 250μm at the hydrophobic surface. On the other hand, the slip length (i.e. hydraulic resistance) decreases with increasing contact angle, e.g. -3μm at the superhydrophilic surface and 10?m at the hydrophobic surface.