Modeling of Microfluidic Capillary Pressure in Microstructures by Surface Evolver Software

Authors

Abstract

The topology, geometry and contact angle of microstructures play a crucial role in determining their capillarity performance. In the present study, the capillary pressure of liquid in microstructure topologies , viz., sphere, circular and square pillars has been investigated numerically. In order to estimate the capillary pressure as the change in interfacial energy per unit volume, the shape of liquid interface in the microstructures are determined using a surface-energy minimization algorithm by coding in a software. Capillary pressure of microspheres in different contact angles are verified with comparision to other results. Capillary pressure presented versus non-dimensional geometrical parameters characterizing the microstructures and the contact angle between the liquid and solid. Based on these performance parameters, packed spheres on a surface are identified to be the most efficient microstructure geometry for capillarity. Also, square pillars are shown to have higher capillary pressure compared with hexagonal arrays of circular pillars with same solid fraction and pitch. The obtained results from microfluidic capillary pressure in microstructures can be used in different science such as agricultural, textile and polymer, petroleum and heat transfer.

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