Characterization of capillary rise dynamics in parallel micro V-grooves

Capillary rise in micro grooves shows its widespread applications in microfluidics in a wide range of areas, such as heat transfer devices, fluids management, polymer films and many other fields. The present study examines the capillary rise in copper micro V-grooves using two liquid acetone and ethanol. An infrared (IR) thermal imaging method was utilized to register the liquid front. Different groove samples with five groove depths from 500 mu m to 850 mu m and four groove widths ranged from 400 mu m to 600 mu m were characterized. The experimental results were compared to the theoretical models to assess the flow kinetics of capillary rise. It was found that the capillary rise in these micro V-grooves firstly followed the Washburn relation (h(t) similar to t(1/2)), then was governed by the h(t) similar to t(1/3) as similar as the dynamics of liquid rise in corners or wedges, and finally exhibited the exponential dynamics. The one-third powder law should be modified by incorporation of the contact angle term, whereas the groove geometry showed negligible effect on this kinetics. (C) 2014 Elsevier Ltd. All rights reserved.