DPG Phi
Verhandlungen
Verhandlungen
DPG

Berlin 2008 – scientific programme

Parts | Days | Selection | Search | Downloads | Help

CPP: Fachverband Chemische Physik und Polymerphysik

CPP 22: POSTERS Micro- and Nanofluidics

CPP 22.7: Poster

Wednesday, February 27, 2008, 16:00–18:30, Poster A

Two-dimensional gas-liquid two-phase flow in a microfluidic device — •Yasutaka Iwashita1, Ralf Seemann1,2, Christian Bahr1, and Stephan Herminghaus11MPI for Dynamics and Self-Organization, 37073 Göttingen, Germany — 2Experimental Physics, Saarland University, 66041 Saarbrücken, Germany

Monodisperse emulsions with a high volume fraction of the dispersed phase can be produced using step emulsification [1]: A quasi 2D-liquid stream of a dispersed phase surrounded by a continuous phase in a shallow channel is transformed into droplets at a topographic step by a Rayleigh-Plateau-type instability.

Here we replace the dispersed liquid by gas and study the gas-liquid two-phase flow in a similar microfluidic device. Due to the compressibility and lower viscosity of gas (more than 100 times smaller than liquid) the dynamics of the quasi 2D, two-phase flow is different from that of liquids. By observing the flow we found three characteristic flow structures: (i) gas-liquid co-flow at high pressure (or large flow rate) of gas, (ii) bubble generation at the T-junction of the shallow channel and (iii) liquid one-phase flow when the gas pressure is lower than the liquid pressure at the T-junction. We will show how these flow structures depend on the conditions (height of the shallow channel, interfacial tension, etc.), and explain the findings with a "simple" theoretical analysis.

[1] C. Priest, S. Herminghaus and R. Seemann, Appl. Phys. Lett. 88, 024106 (2006)

100% | Mobile Layout | Deutsche Version | Contact/Imprint/Privacy
DPG-Physik > DPG-Verhandlungen > 2008 > Berlin