Abstract
Surface tension force plays an important role on microchannel flows and it directly relates to the contact angle of liquid on solid. The movement of a liquid slug inside a microchannel experiences different forces balance and the changing shape of the liquid slug is in different pattern especially if there is any irregular shape inside the microchannel. A micro-well of MEMS device can serve the purpose as a micro-reservoir and the well needs to be filled with liquid slug in many biomedical applications. Numerical Simulations of the filling process are performed by solving equations similar to homogenous flow model used in two phase flow calculation in cooperation with Volume-of-Fluid (VOF) interface tracking methodology and Continuum Surface Force (CSF) model. This paper has demonstrated the successful simulation of a surface tension dominated flow inside a micro channel containing a well with 45° inclined wall. Three cases, 30° for hydrophilic, 120° for hydrophobic, and 90° in between, have been studied in detail and the results show that with proper well shape and size design, liquid can be remained inside the well in the case of hydrophilic channel inner surface. © 2000 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.