Effect of Shear Rate on Non-Newtonian Droplet Generation in T-junction Microfluidic System

Abstract

AbstractMono-dispersed droplet generation in T-junction microchannel is carried out by using the level set method. The dispersed phase fluid is non-Newtonian, and the continuous phase is assumed to be a Newtonian fluid. The flow and phase-field equations are solved for various shear rates (\(1\le \dot{\gamma }\le {10}^{3}\)) using the finite element method. The power-law fluid model is employed to study the dependence of viscosity of the dispersed phase on droplet generation. The influence of the controlling parameters such as flowrates ratio and shear rate ratios on droplet dynamics is systematically studied. The transient flow in the microchannel has revealed the exciting dynamics of droplet formation with the shear-dependent dispersed phase. The flow regimes have been classified into droplet and non-droplet zones by the power-law index (\(n\)) at different shear rates. It is observed that there is a droplet formation at lower values of flowrate ratio (\({Q}_{r}<1\)) for shear-thinning (n < 1) fluids for a specific range of \(\dot{\gamma }\). However, the flow is becoming parallel at a higher flowrate ratio (\({Q}_{r}>1\)). For a fixed flowrate ratio and shear rate, there is a droplet generation for shear-thinning fluids, and whereas the flow is becoming parallel in the case of shear thickening fluids.KeywordsTwo-phase flowNon-Newtonian fluidthe level set methodDroplet generation