The Flow of Liquids in Surface Grooves

Abstract

We have obtained detailed capillary kinetic data for flow of a series of alcohols with various surface tension to viscosity ratios, {gamma}/{mu}, spreading in open V-shaped grooves cut in Cu with three different groove angles. Two theoretical models which assume Poiseuille flow and static advancing contact angles were tested against the experimental data. One is a detailed hydrodynamic model with the basic driving force resulting from the pressure drop across a curved interface. The second depends on the total interfacial energy change, independent of the shape of the liquid interface. Both agree with the experimental data. Both predict numerical values in general agreement with experiment and with each other. In the threshold region where the transition occurs between filled and empty regions of the groove, the liquid height decreases linearly with distance, within experimental limitations, and forms an angle which roughly scales as the contact angle for a significant fraction of the threshold region. On the basis of the present detailed experimental data for both kinetics and threshold profile, the differences between experiment and theory and between the theoretical models are insufficient to allow a clear choice between the models. 20 refs., 11 figs., 3 tabs.