The magnitude of lift forces acting on drops and bubbles in liquids flowing inside microchannels

Claudiu A. Stan; Audrey K. Ellerbee; Laura Guglielmini; Howard A. Stone; George M. Whitesides

doi:10.1039/C2LC41035D

The magnitude of lift forces acting on drops and bubbles in liquids flowing inside microchannels†

Claudiu A. Stan,*^a Audrey K. Ellerbee,^b Laura Guglielmini,^c Howard A. Stone^d and George M. Whitesides^b

* Corresponding authors

^a Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
E-mail: claudiu.stan@alum.mit.edu

^b Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA

^c Center for Turbulence Research, Stanford University, Stanford, CA 94305, USA

^d Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544, USA

Abstract

Hydrodynamic lift forces offer a convenient way to manipulate particles in microfluidic applications, but there is little quantitative information on how non-inertial lift mechanisms act and compete with each other in the confined space of microfluidic channels. This paper reports measurements of lift forces on nearly spherical drops and bubbles, with diameters from one quarter to one half of the width of the channel, flowing in microfluidic channels, under flow conditions characterized by particle capillary numbers Ca_P = 0.0003–0.3 and particle Reynolds numbers Re_P = 0.0001–0.1. For Ca_P < 0.01 and Re_P < 0.01 the measured lift forces were much larger than predictions of deformation-induced and inertial lift forces found in the literature, probably due to physicochemical hydrodynamic effects at the interface of drops and bubbles, such as the presence of surfactants. The measured forces could be fit with good accuracy using an empirical formula given herein. The empirical formula describes the power-law dependence of the lift force on hydrodynamic parameters (velocity and viscosity of the carrier phase; sizes of channel and drop or bubble), and includes a numerical lift coefficient that depends on the fluids used. The empirical formula using an average lift coefficient of ∼500 predicted, within one order of magnitude, all lift force measurements in channels with cross-sectional dimensions below 1 mm.

Supplementary files

Article information

DOI: https://doi.org/10.1039/C2LC41035D
Article type: Paper
Submitted: 11 Sep 2012
Accepted: 08 Nov 2012
First published: 09 Nov 2012

Download Citation

Lab Chip, 2013,13, 365-376

Permissions

Request permissions

The magnitude of lift forces acting on drops and bubbles in liquids flowing inside microchannels

C. A. Stan, A. K. Ellerbee, L. Guglielmini, H. A. Stone and G. M. Whitesides, Lab Chip, 2013, 13, 365 DOI: 10.1039/C2LC41035D

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Lab on a Chip

The magnitude of lift forces acting on drops and bubbles in liquids flowing inside microchannels†

Abstract

Associated articles

Supplementary files

Article information

Download Citation

Permissions

The magnitude of lift forces acting on drops and bubbles in liquids flowing inside microchannels

Social activity

Search articles by author

Spotlight

Advertisements