Authors: H.Q. Yang and A.J. Przekwas
Affilation: CFD Research Corporation, United States
Pages: 498 - 505
Keywords: CFD, Microfluidic, MEMS
Integrated Microfluidic Systems are the subject of great scientific and commercial interest for a wide range of applications, including the biomedical, environmental, automotive, aerospace, and defense. This paper presents the computational methodology used in the ACE+MEMS CAD Software for design of fluidic devices incorporating free surface. The flow physics of the multi-fluid flow is solved with full Navier Stokes equations on 3-D unstructured grids. The unsteady motion of the free surface governed by the Hamilton-Jacobi evolution equation is solved on Eulerian grid using the Volume of Fluid (VOF) technique. Higher order surface reconstruction algorithms on unstructured grids are employed to predict the free surface shape. To predict the surface tension effects, the Laplace-Young high-order nonlinear boundary conditions at the liquid su.-face are needed to accurately model the liquid-gas interface and at the wall contact. For MEMS applications with a large aspect ratio geometry, the code allows mxed-dimensionality simulations in which 3-D domains are interfaced with 2-D channels. In reduced dimension channels, the Hele-Shaw model can be used for the free surface simulations. The paper presents basic mathematical formulation and numerical techniques used. The computational techniques and the software are validated/demonstrated on several MEMS microfluidic devices.