COMPUTATIONAL STUDY OF VISCOELASTIC FLOWS IN MICROCHANNELS

Computational Fluid Dynamics (CFD) simulations have been performed in a 2D cross-section of the microchannel to characterize the viscoelastic flow field using OpenFOAM with customized stabilizing methods. The continuity and momentum equations coupled with the Giesekus constitutive model are solved. The computational domain consists of a straight main channel that is 100 mu m in width and a 1:4 square-shaped cavity in the middle of the channel. The mesh convergence study is performed with both structured and unstructured cells. Flow and stress fields are compared with different cell densities. The numerical study is carried out on various Deborah numbers (De). The first normal stress difference is computed to examine the elastic lift force for future studies for nanoparticle separations. The vortex on the expansion side shrinks while the contraction side expands as De is increased. A banded zone of stronger N1 in the bulk region of the cavity, observed at higher De, could be favorable in particle separation applications. As the simulation process being validated, this study can help with future improvements to achieve higher flow rates.