Optimised cross-slot microdevices for homogeneous extension

Francisco J Galindo-Rosales, Monica Oliveira, M.A. Alves

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

Microfluidic cross-slot devices can generate wide regions of vorticity-free strong extensional flow near the stagnation point, resulting in large extensional deformation and orientation of the microstructure of complex fluids, with possible applications in extensional rheometry and hydrodynamic stretching of single cells or molecules. Standard cross-slot devices, with sharp or rounded corners, generate a flow field with a non-homogeneous extension rate that peaks at the stagnation point, but decays significantly with distance from the stagnation point. To circumvent this limitation, an optimized shape cross-slot extensional rheometer (OSCER) was designed numerically and shown to generate constant extension rate over a wide region of the in- and out-flowing symmetry planes [Haward et al., Phys. Rev. Lett., 2012, 109, 128301]. Since the OSCER device was based on a 2D flow approximation, the practical implementation requires a large aspect ratio, which cannot be reproduced by standard soft-lithography techniques. Here, we propose a set of new designs for optimized cross-slot geometries, considering aspect ratios of order 1 and different lengths of the homogeneous inlet/outlet-flow regions. Micro-particle image velocimetry experiments were carried out in order to validate the flow kinematics, and the velocity profiles were found to be linear along the in- and outflow centrelines in good quantitative agreement with the numerical predictions.
LanguageEnglish
Pages7799-7804
JournalRSC Advances
Volume4
Issue number15
DOIs
Publication statusPublished - Jan 2014

Fingerprint

Rheometers
Aspect ratio
Inlet flow
Vorticity
Microfluidics
Velocity measurement
Lithography
Stretching
Flow fields
Kinematics
Hydrodynamics
Microstructure
Molecules
Fluids
Geometry
Experiments

Keywords

  • microdevices
  • cross-slot device
  • homogeneous

Cite this

Galindo-Rosales, Francisco J ; Oliveira, Monica ; Alves, M.A. / Optimised cross-slot microdevices for homogeneous extension. In: RSC Advances. 2014 ; Vol. 4, No. 15. pp. 7799-7804.
@article{982bef387a634e64b61f2b75395c6769,
title = "Optimised cross-slot microdevices for homogeneous extension",
abstract = "Microfluidic cross-slot devices can generate wide regions of vorticity-free strong extensional flow near the stagnation point, resulting in large extensional deformation and orientation of the microstructure of complex fluids, with possible applications in extensional rheometry and hydrodynamic stretching of single cells or molecules. Standard cross-slot devices, with sharp or rounded corners, generate a flow field with a non-homogeneous extension rate that peaks at the stagnation point, but decays significantly with distance from the stagnation point. To circumvent this limitation, an optimized shape cross-slot extensional rheometer (OSCER) was designed numerically and shown to generate constant extension rate over a wide region of the in- and out-flowing symmetry planes [Haward et al., Phys. Rev. Lett., 2012, 109, 128301]. Since the OSCER device was based on a 2D flow approximation, the practical implementation requires a large aspect ratio, which cannot be reproduced by standard soft-lithography techniques. Here, we propose a set of new designs for optimized cross-slot geometries, considering aspect ratios of order 1 and different lengths of the homogeneous inlet/outlet-flow regions. Micro-particle image velocimetry experiments were carried out in order to validate the flow kinematics, and the velocity profiles were found to be linear along the in- and outflow centrelines in good quantitative agreement with the numerical predictions.",
keywords = "microdevices, cross-slot device, homogeneous",
author = "Galindo-Rosales, {Francisco J} and Monica Oliveira and M.A. Alves",
note = "Date of Acceptance: 02/01/2014 Online Publication",
year = "2014",
month = "1",
doi = "10.1039/c3ra47230b",
language = "English",
volume = "4",
pages = "7799--7804",
journal = "RSC Advances",
issn = "2046-2069",
number = "15",

}

Optimised cross-slot microdevices for homogeneous extension. / Galindo-Rosales, Francisco J; Oliveira, Monica; Alves, M.A.

In: RSC Advances, Vol. 4, No. 15, 01.2014, p. 7799-7804.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Optimised cross-slot microdevices for homogeneous extension

AU - Galindo-Rosales, Francisco J

AU - Oliveira, Monica

AU - Alves, M.A.

N1 - Date of Acceptance: 02/01/2014 Online Publication

PY - 2014/1

Y1 - 2014/1

N2 - Microfluidic cross-slot devices can generate wide regions of vorticity-free strong extensional flow near the stagnation point, resulting in large extensional deformation and orientation of the microstructure of complex fluids, with possible applications in extensional rheometry and hydrodynamic stretching of single cells or molecules. Standard cross-slot devices, with sharp or rounded corners, generate a flow field with a non-homogeneous extension rate that peaks at the stagnation point, but decays significantly with distance from the stagnation point. To circumvent this limitation, an optimized shape cross-slot extensional rheometer (OSCER) was designed numerically and shown to generate constant extension rate over a wide region of the in- and out-flowing symmetry planes [Haward et al., Phys. Rev. Lett., 2012, 109, 128301]. Since the OSCER device was based on a 2D flow approximation, the practical implementation requires a large aspect ratio, which cannot be reproduced by standard soft-lithography techniques. Here, we propose a set of new designs for optimized cross-slot geometries, considering aspect ratios of order 1 and different lengths of the homogeneous inlet/outlet-flow regions. Micro-particle image velocimetry experiments were carried out in order to validate the flow kinematics, and the velocity profiles were found to be linear along the in- and outflow centrelines in good quantitative agreement with the numerical predictions.

AB - Microfluidic cross-slot devices can generate wide regions of vorticity-free strong extensional flow near the stagnation point, resulting in large extensional deformation and orientation of the microstructure of complex fluids, with possible applications in extensional rheometry and hydrodynamic stretching of single cells or molecules. Standard cross-slot devices, with sharp or rounded corners, generate a flow field with a non-homogeneous extension rate that peaks at the stagnation point, but decays significantly with distance from the stagnation point. To circumvent this limitation, an optimized shape cross-slot extensional rheometer (OSCER) was designed numerically and shown to generate constant extension rate over a wide region of the in- and out-flowing symmetry planes [Haward et al., Phys. Rev. Lett., 2012, 109, 128301]. Since the OSCER device was based on a 2D flow approximation, the practical implementation requires a large aspect ratio, which cannot be reproduced by standard soft-lithography techniques. Here, we propose a set of new designs for optimized cross-slot geometries, considering aspect ratios of order 1 and different lengths of the homogeneous inlet/outlet-flow regions. Micro-particle image velocimetry experiments were carried out in order to validate the flow kinematics, and the velocity profiles were found to be linear along the in- and outflow centrelines in good quantitative agreement with the numerical predictions.

KW - microdevices

KW - cross-slot device

KW - homogeneous

UR - http://pubs.rsc.org/En/content/articlelanding/2014/ra/c3ra47230b#divAbstract

U2 - 10.1039/c3ra47230b

DO - 10.1039/c3ra47230b

M3 - Article

VL - 4

SP - 7799

EP - 7804

JO - RSC Advances

T2 - RSC Advances

JF - RSC Advances

SN - 2046-2069

IS - 15

ER -