Bubble removal is made easier as scientists identify mechanisms for bubble release in shear-thinning fluids

When processing complex fluids, the presence of bubbles can cause quality-related issues such as reduced mechanical properties, bacterial contamination, instability or intermittent flow regimes in microfluidics. Bubble removal is the best way to prevent these issues, but current techniques to do so usually require expensive or bulky equipment.

De Corato et al. discovered by building upon previous experimental observations, they found a correlation between the shear-thinning properties of a fluid and the enhanced rising velocity of pulsating bubbles. They confirmed this by using theory and numerical simulations, proving radial pulsations of a bubble suspended in a shear-thinning fluid caused it to rise faster in the fluid.

By controlling and understanding this factor, the authors linked the enhancement of the rising velocity to the properties of the fluid and the frequency of the bubble pulsations.

“This information might be interesting for companies that have to remove bubbles from their processing fluids and need to select the appropriate external driving parameters to maximize the process efficiency,” author Marco De Corato said.

The authors want to build upon this research by studying the effects of fluid elasticity on the rise of pulsating bubbles. They theorize elastic response of the fluid slows down the rising velocity of bubbles and intend on quantifying the impact of the response in future simulations.

Source: “The rising velocity of a slowly pulsating bubble in a shear-thinning fluid,” by Marco De Corato, Yannis Dimakopoulos, and John Tsamopoulos, Physics of Fluids (2019). The article can be accessed at https://doi.org/10.1063/1.5108812 .