Formation characteristics of Taylor bubbles in power-law liquids flowing through a microfluidic co-flow device

TL;DR

This study numerically investigates the formation and dynamics of Taylor bubbles in power-law liquids within microchannels, revealing how concentration, velocities, and surface tension influence bubble behavior and identifying different flow regimes.

Contribution

It introduces a detailed numerical analysis of Taylor bubble formation in power-law fluids in microfluidic co-flow devices, including flow pattern maps and scaling laws.

Findings

Different bubble breakup mechanisms observed at various PAAm concentrations.

Two distinct flow regimes identified based on bubble length relative to channel diameter.

Flow pattern maps and scaling laws developed for bubble length estimation.

Abstract

Formation and dynamics of Taylor bubble in power-law liquids flowing through a circular co-flow microchannel are numerically investigated using coupled level set and volume-of-fluid method. Aqueous solutions of polyacrylamide (PAAm) are used as power-law liquids. Influences of PAAm concentration, gas-liquid velocities, and surface tension on bubble characteristics are explored. Various mechanism of bubble breakup are observed in different concentration of PAAm. Based on the bubble length with respect to the channel diameter, two different flow regimes are identified. Flow pattern maps are constructed based on inlet velocities, and scaling laws are proposed to estimate the bubble length.