Bubble Production Mechanism in a Microfluidic Foam Generator

Maximilien Stoffel (1) , Sebastian Wahl (1) , Elise Lorenceau (2, 3) , Reinhard Höhler (3, 4) , Bruno Mercier (1) , Dan E. Angelescu (1)

1 ESYCOM - Electronique, Systèmes de communication et Microsystèmes
2 Rhéophysique
3 LPMDI - Laboratoire de Physique des Matériaux Divisés et des Interfaces
4 INSP - Institut des Nanosciences de Paris

We present the design and characterization of a microfluidic bubble generator that has the potential of producing monodisperse bubbles in 256 production channels that can operate in parallel. For a single production channel we demonstrate a production rate of up to 4 kHz with a coefficient of variation of less than 1%. We observe a two-stage bubble production mechanism: initially the gas spreads onto a shallow terrace, and then overflows into a larger foam collection channel; pinning of the liquid-gas meniscus is observed at the terrace edge, the result being an asymmetric pinch-off. A semiempirical physical model predicts the scaling of bubble size with fluid viscosity and gas pressure from measurements of the pinned meniscus width.

Domaines: Dynamique des Fluides [physics.flu-dyn]

Maximilien Stoffel, Sebastian Wahl, Elise Lorenceau, Reinhard Höhler, Bruno Mercier, et al.. Bubble Production Mechanism in a Microfluidic Foam Generator. Physical Review Letters, 2012, 108, pp.198302. ⟨10.1103/PhysRevLett.108.198302⟩. ⟨hal-00785723⟩