EXPERIMENTAL TECHNIQUES FOR THE ANALYSIS OF GAS …

EXPERIMENTAL TECHNIQUES FOR THE ANALYSIS OF GAS MICROFLOWS

64th IUVSTA WorkshopLeinsweiler – May 16-19, 2011

Stéphane COLIN

2 Leinsweiler - May 16-19, 2011Experimental techniques for the analysis of gas microflows - S. Colin

Motivation for Experimental Analysis of Gas Microflows

Wide literature on modelling and numerical simulation of gas microflows, in different rarefaction regimes

However, few available experimental data Crucial need of smart experimental data, for example to:

– Help identifying the best BC to be used in slip flow regime and the limit of applicability of the associated analytical models

– Analyse the influence of surface, which may vary with different materials – silicon, metals, polymers, glass and fused silica… different kind of manufacturing – wet chemical etching, reactive ion

etching, laser etching, moulding, embossing, drilling, micromilling…

INTRODUCTION


Slip Flow Regime: Some Examplesof Various Velocity Slip Boundary Conditions

Initial form– Maxwell, J.C. (1879) Philosophical

Transactions of the Royal Society,170, 231-256.

22 3 32 4

u tt wall

u

u T Tu un T s t T t

INTRODUCTION





Curvature effects– Barber, R.W., et al. (2004) Vacuum, 76, 73-81.

2 34

u t nt wall

u

u u R Tu un t p t

22 3 32 4

u tt wall

u

u T Tu un T s t T t

INTRODUCTION






Higher-order forms– Deissler, R.G. (1964) International

Journal of Heat and Mass Transfer,7, 681-694.

2 34

u t nt wall

u

u u R Tu un t p t

22 3 32 4

u tt wall

u

u T Tu un T s t T t

2 2 22

2 2 2

2 9 216

u t t t tt wall

u

u u u uu un n s t

INTRODUCTION






Higher-order forms– Deissler, R.G. (1964) International


Other hybrid dimensionless forms– Karniadakis, G.E. & Beskok, A. (2002) Microflows:

Fundamentals and Simulation, Springer-Verlag.– Xue, H. & Fan, Q. (2000) Microscale Thermophysical

Engineering, 4, 125-143.– Jie, D., et al. (2000) Journal of

Micromechanics and Microengineering, 10, 372-379.

2 34

u t nt wall

u

u u R Tu un t p t

22 3 32 4

u tt wall

u

u T Tu un T s t T t

21 *

u tt wall

u

Kn uu ub Kn n

2 tanh*

u tt wall

u

uu u Knn

2 * ** ** 2 *

u tt wall

u

u Kn pu u Kn Ren t

2 2 22

2 2 2

2 9 216

u t t t tt wall

u

u u u uu un n s t

INTRODUCTION


Slip Flow Regime: Examples of Temperature Jump Boundary Conditions

Initial form– Smoluchowski, M. (1898) Annalen

der Physik und Chemie,64, 101-130.

Additional term– Sparrow, E. M. & Lin, S. H.

(1962) Journal of Heat Transfer, 84, 363-369.

Higher-order forms– Deissler, R. G. (1964) International


Langmuir boundary condition– Myong, R. S., et al. (2006) International


INTRODUCTION

2 21

Twall

T

TT TPr n

2 2 2 2

2 2 2

2 21

177 145 9 21 256

Twall

T

TT TPr n

T T Tn t s

1wall nT aT a T

22 2 4 1

1 1 2t wallT T u

wallT T u p

u uTT TPr n c


Experimental Analysis of Gas Microflows

Example: gas flow in a microchannelMain quantities of interest

Mass flowrate

GLOBAL data

Dijkstra, M., et al. (2008) Sensors and Actuators A: Physical,143, 1-6.

INTRODUCTION

Pressure

Temperature

Velocity

LOCAL data

Concentration


Flowrate Measurement

http://www.bronkhorst.com Limits of commercial mass flow meters

– around 10-8 kg/s Ex. Bronkhorst F-110C

– 0,014 to 0,7 sccm – Accuracy ± 0.5% Rd

plus ± 0.1% FS– Thermal principle

p

mk c T

FLOWRATE


Flowrate Measurement

p VmR T

1 dV dp pV dTm p VR T dt dt T dt

Tank

(m, p, T, V)

m

µsystem

Constant Pressure Method

FLOWRATE

Constant Volume Method

Droplet Tracking Method

For lower flowrates: need of specific setups

Basic principle based on the equation of state – suitable for dilute gases

with good thermal insulation


Droplet Tracking MethodPrinciple

FLOWRATE

4.0E-10

6.0E-10

8.0E-10

1.0E-09

1.2E-09

1.4E-09

0 2 4 6 8 10 12

mesure n°

Q (m

3 /s)

volume mean flow rates

4.0E-10

6.0E-10

8.0E-10

1.0E-09

1.2E-09

1.4E-09

0 2 4 6 8 10 12

mesure n°

Q (m

3 /s)


Volume flowrate

2Q

1Q

Lalonde, P. (2001) PhD Thesis, INSA Toulouse.


Droplet Tracking MethodPrinciple

FLOWRATE

1 1 11 1 1

0 1

ii i

i

Q V Vm P P PRT V V

2 2 22 2 2

3 2

ii i

i

Q V Vm P P PRT V V

Mass flowrate

V0 ; P0 V3 ; P3V1 ; P1 V2 ; P2µS

1m 2m

drop drop

4.0E-10

6.0E-10

8.0E-10

1.0E-09

1.2E-09

1.4E-09

0 2 4 6 8 10 12

mesure n°

Q (m

3 /s)


4.0E-10

6.0E-10

8.0E-10

1.0E-09

1.2E-09

1.4E-09

0 2 4 6 8 10 12

mesure n°

Q (m

3 /s)


Volume flowrate

2Q

1Q

Lalonde, P. (2001) PhD Thesis, INSA Toulouse.


Droplet Tracking MethodExample of Results

Flow of N2 and He in rectangular microchannels

FLOWRATE

0,0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,8

0,9

1,0

0 0,1 0,2 0,3 0,4 0,5

NS1

NS2

h hgas

1.88µm

1.66 µm

0.54 µm

N2

He

1.8i

o

PP

Colin, S., et al. (2004) Heat Transfer Engineering, 25, 23-30.o oKn h

no slip

slip

m

m

2 u tt wall

u

uu un

2 2 22

2 2 2

2

9 216

u tt wall

u

t t t

uu un

u u un s t


Réservoiramont

Réservoiraval

MicrosystèmeUpstream

tank

Downstream tank

Microsystem

2% P P

V Pm

rT t

P t

T t P t

Constant Volume MethodPrinciple


Constant Volume MethodSetup

Pitakarnnop, J., et al. (2010) Microfluidics and Nanofluidics, 8, 57-72.

Reservoir A

Reservoir B

FLOWRATE


Kn010-210-1100101

Constant Volume MethodExample of Results

Pitakarnnop, J., et al. (2010) Microfluidics and Nanofluidics, 8, 57-72.

FLOWRATE


Main Flowrates Data on Gas Microflows

Droplet tracking method– Pong, K.-C., et al. (1994) FED-197, ASME, New York, pp. 51-56.– Harley, J. C., et al. (1995) Journal of Fluid Mechanics, 284, 257-274.– Zohar, Y., et al. (2002) Journal of Fluid Mechanics, 472, 125-151.– Maurer, J., et al. (2003) Physics of Fluids, 15, 2613-2621.– Colin, S., et al. (2004) Heat Transfer Engineering, 25, 23-30. – Ewart, T., et al. (2006) Experiments in Fluids, 41, 487-498.

Constant pressure method– Jousten, K., et al. (2002) Metrologia, 39, 519-529.

Constant volume method– Arkilic, E. B., et al. (1998) Experiments in Fluids, 25, 37-41 – Arkilic, E. B., et aL. (2001) Journal of Fluid Mechanics, 437, 29-43.– Ewart, T., et al. (2007) Journal of Fluid Mechanics, 584, 337-356.– Pitakarnnop, J., et al. (2010) Microfluidics and Nanofluidics, 8, 57-72.– Szalmás, L., et al. (2010) Microfluidics and Nanofluidics, 9, 1103-1114.

(mixtures of gases)

FLOWRATE


Pressure Measurements – Discrete Data

Shih, J. C et al. (1996), ASME DSC-59, pp. 197-203.– First local data for gas flows in microchannels – Channel 4,000×40×1.2 µm3

– He & N2 Zohar, Y. et al. (2002) Journal of Fluid Mechanics, 472, 125-151.

– Detailed measurements– Channels 4,000×40×(0.53 & 0.97) µm3

– He, Ar & N2 Jang, J. & Wereley, S. T. (2004) Microfluidics and Nanofluidics, 1, 41-51.

– Rectangular channels with higher aspect ratio (0.36)– Channels ?×105×39 µm3

– Air Turner, S. E. et al. (2004) Journal of Heat Transfer, 126, 753-763.

– Entrance effects analysed; influence of roughness 0.4 % to 6 %: insignificant– Channel 30,000×1,000×(2.3 to 50) µm3

– Air

2(He) (N )0.16 or 0.055oKn

2(Ar) (N )0.20 or 0.067oKn

0.0018oKn

PRESSURE

0.15oKn


Pressure Measurement

Integrated pressure sensors

Zohar, Y. et al. (2002) Journal of Fluid Mechanics, 472, 125-151.

• Microchannel• length 4000 µm• width 40 µm• depth 0.5 or 1 µm

• Capillary connection• width 4 µm• depth 0.2 µm

PRESSURE




Nitrogen flow• channel depth0.97 µm• outlet pressure100 kPa• accuracy ± 5 %Model• first order slip flow• plane flow• diffuse accommodation

0.067oKn

PRESSURE




Shih, J. C et al. (1996), ASME DSC-59, pp. 197-203.

Argon flow• channel depth0.53 µm• outlet pressure100 kPa• accuracy ± 5 %Model• first order slip flow• plane flow• diffuse accommodation

0.20oKn

Helium flow, channel depth 1.2 µm

PRESSURE


Measurements of Pressure Fieldsat the Wall

Pressure-sensitive paints (PSP)– Luminescent molecules coated at the wall; once excited, emit at a longer

wavelength– Luminescent intensity depends on O2 concentration (oxygen quenching

phenomenon), related to pressure– Non intrusive technique - High spatial resolution– Need calibration and transparent side – Cannot be used for oxygen free gases– Too thick for use at microscale

Huang, C. et al. (2007) Journal of Microelectromechanical Systems, 16, 777-785. Pressure-sensitive molecular films (PSMF)

– Technique developed at Nagoya University Mori, H. et al. (2005) Physics of Fluids, 17, 100610. Matsuda, Y. et al. (2007) Experiments in Fluids, 42, 543-550. Matsuda, Y., et al. (2009) Experiments in Fluids, 47, 1025-1032. Matsuda, Y., et al. (2011) Microfluidics and Nanofluidics, 10, 165-171.

PRESSURE


Pressure-Sensitive Molecular Films (PSMF)

Example of luminophore:Pt(II) Mesoporphyrin IX

Langmuir–Blodgett (LB)deposition method

Matsuda, Y. et al. (2009) Experiments in Fluids, 47, 1025-1032.

PRESSURE


From PSP to PSFM

Relative luminescent intensity fields - 160×160 µm2 surface

Matsuda, Y. et al. (2011) Microfluidics and Nanofluidics, 10, 165-171.

PSPStandard deviation 0.23

PSFMStandard deviation 0.016

PRESSURE


Experimental Results

Micro-nozzle flow– 2 configurations– Pi = 10 kPa– Po = 1 kPa


PRESSURE


PSMF – Comparison with DSMC

Pressure distribution Pressure along the centerline


PRESSURE


PSMF – Comparison with DSMC

Pressure distribution Pressure along the centerline


PRESSURE


Temperature Measurement

Various available techniques for measurement at the wall – Thin film Resistance Thermo Detectors (RTD)– Thin Film ThermoCouples (TFTC)

25x25 µm2 to 80x80 µm2 embedded junction in a 100-150 nm thick film. 20 °C – 900 °CZhang, X., et al. (2006) Journal of Micromechanics and Microengineering,16, 900.

– Semiconducting Sensors (SC)– Temperature sensitive paint (TSP)

Promising new techniques for measurement within the flow – Molecular Tagging Thermometry (MTT)

Hu, H., et al. (2010) Measurement Science and Technology, 21,085401:1-14

TEMPERATURE


Velocity Measurement

VELOCITY

Two recent techniques (for gas) currently under investigation

– Micro Particule Image Velocimetry (µPIV)

– Micro Molecular Tagging Velocimetry (µMTV)


Principle of classic PIV

http://www.dantecdynamics.com

VELOCITY


Difference Between PIV and µPIV

VELOCITY

http://www.dantecdynamics.com

Meinhart, C. D. et al. (2000) Measurement Science and Technology, 11, 809-814.


µPIV for Air Flow in Square Microchannels

Yoon, S. Y. R. et al. (2006) Journal of Power Sources, 160, 1017-1025.

VELOCITY

Square sections– 1×1 mm2

Tracers– smoke particles – water droplets

Re = 50 - 820 spatial resolution

– 40 - 60 µm Not in rarefied regimes


µPIV for Nitrogenin Rectangular Channels

Rectangular channels– 1 mm × 0.5 mm

Tracers– fluorescent oil droplets– diameter 0.5 to 2 µm

Re = 26 – 130 Not in rarefied regimes

Sugii, Y. and Okamoto, K. (2006) In Proceedings of ICNMM2006, Limerick, pp. ICNMM2006-96216:1-6.

VELOCITY


Molecular Tagging Velocimetry (MTV) Principle

VELOCITY

Direct UV tagging of specific molecules– Once excited: immediate fluorescence– After a delay: phosphorescence

Efficient with liquids– Supramolecules

Only tested with gases in unconfined flows

– Acetone & Biacetyl


Micro Molecular Tagging Velocimetry & Thermometry (µMTV-µMTT) in Liquids

Current data on microflows only for liquids. Examples:

– µMTV in a Hagen-Poiseuille flow in a fused silica microtube

– µMTV and µMTT in electro osmotic flow

VELOCITY

Maynes, D. and Webb, A. R. (2002) Experiments in Fluids, 32, 3-15.

t 200 µs

Hu, H., et al. (2010) Measurement Science and Technology, 21, 085401:1-14.

t 4.5 ms


µMTV with Gast 2.5 µs

t 4.5 µs

t 6.5 µs

t 8.5 µs

Very preliminary results– Ar flow seeded with acetone molecules– 1 mm deep rectangular microchannel– Near atmospheric conditions (no rarefaction)

Samouda, F., et al. (2011) Proceedings of GASMEMS11, Bertinoro, Italy.


µMTV with Gas: Delicate Choice of Material for the Walls

Fluorescence images obtained in TSC3 (a) and Suprasil (b) channels

Samouda, F., et al. (2011) Proceedings of GASMEMS11, Bertinoro, Italy.

(a) (b)


Conclusions

Validated accurate techniques for flow rates measurements– All Knudsen regimes are covered – database is currently developing for single

gases and mixtures in various microchannels sections– Typical uncertainty around ± 4% - can be still improved?– Still work to do for various controlled temperature and wall surface conditions

Recent promising techniques for pressure and temperature field analysis– Local microsensors: data at precise locations at the wall– PSMF for pressure field at the wall– Very few data on microscale heat transfer for gases– µMTT to be developed for obtaining data within the flow

Preliminary steps in velocity field analysis– µPIV and µMTV for confined flows– Still no data for rarefied flows – challenging for measurement of slip at the wall

Analysis of mixing of gases or separation in gas mixtures in microsystems– Interferometry techniques currently under development


Acknowledgements

Organizers of 64th

IUVSTA Workshop

Funding from European Community's 7th Programme FP7/2007-2013 under grant agreement ITN GASMEMS n°215504


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EXPERIMENTAL TECHNIQUES FOR THE ANALYSIS OF GAS …

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