Development of a new opposed-nozzle fixture for measuring the … · 2016. 2. 12. · fixture for...
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Development of a new opposed-nozzle fixture for measuring the extensional properties of low viscosity liquids
May-August, 2009 – MIT, Harvard University and University of Minnesota
1
J. Soulages,
G. H. McKinley
F. Le Goupil,
J. Hostettler,
Motivation
• RFX instrument by Rheometrics • ARES-G2 Add-on
• P. Dontula et al., “Can extensional viscosity be measured with opposed-nozzle devices?”, Rheol. Acta 36:429-448 (1997) 2
➡ Rheometer add-on to measure the apparent extensional viscosity of low-viscosity fluids at high deformation rates.
• G.G. Fuller et al., J. Rheol. 31:235-249 (1987)
LL
FFF
Working Equations
Extension rate:
Stress on nozzle:
Apparent extensional viscosity:
Volumetric flow rate
Nozzle to nozzle half distance
Force acting on jet Measured torque
Pivot arm length
Nozzle radius
3
Inertia Correction:
P. Dontula et al., Rheol. Acta 36:429-448 (1997)
Liquid density
2d
2r
Q Q
with
10-3 10-2 10-1 100 101 102 103 104 105
10-3
10-2
10-1
100
101
102
103
104
105
106
107
___ 1.37 mm___ 0.84 mm___ 0.51 mm
η E
[Pas
]
dε/dt [s-1]
Previous Work: ARES Operating Region
Minimum flow rate based on syringe pump specifications
Maximum flow rate based on syringe pump specifications
Maximum measurable
viscosity based on the maximum pressure drop
achievable with the syringe pump (8
bar):
ARES minimum resolvable torque
(2x10-6 Nm)
3 x zero-shear viscosity
(η0=0.1 Pas)
4
ARES-G2 minimum
resolvable torque (0.1x10-6 Nm)
Operating Region as a Function of Nozzle
Diameter
Nozzle length ( 8 mm )
*
*assuming
3 x zero-shear viscosity
(η0=0.7 Pas)
0 20 40 60
0.0
1.0x10-6
2.0x10-6
3.0x10-6
4.0x10-6
5.0x10-6
ARES minimum resolvable torque : 2x10-6 Nm
Residual Torque
RFX minimum resolvable torque : 0.5x10-6 Nm
ARES-G2 minimum resolvable torque : 0.1x10-6 Nm
Tor
que
[Nm
]
Time [s]
ARES minimum resolvable torque : 2x10-6 Nm
ARES/ARES-G2 Residual Torques
5
System Definition
Q
++-Suction (b=0)
+-+Expulsion (b=0)
Sign of Minertia
Sign of a Sign of Mmeasured
Mode
xz
y
Top view
F
Pivot Arm L
nozzle
ARES-G2 Torque reading : M > 0
Eps [s-1]
M [N
m]
Eps [s-1]
Expulsion
Suction
4x10-5
-4x10-5
3x104-3x104
ρ = 1225 Kg.m-3
η0 = 0.10 PasKI = 0.3
100 101 102 10310-2
10-1
100
101
η [P
as]
[s-1]
T = 27°C
Pure glycerol (η0 = 0.64 Pas)
Glycerol/Water (88/12 wt%) (η0 = 0.10 Pas)
10-1 100 101 102 103
10-2
10-1
100
101
η [P
as]
[s-1]
Newtonian + PEO solutions with η0 ≈ 0.7 Pas (high viscous set)
• Two sets of fluids :
Working Fluids : Zero-shear-rate Viscosity
Newtonian Fluids7
Non-Newtonian Fluids
T = 27°C
PEO 1wt% in Glycerol/Water (50/50 wt%) (η0 = 0.74Pas)
PEO/Water (1/99 wt%) (η0 = 0.12Pas)
Shear thinning
Newtonian + PEO solutions with η0 ≈ 0.1 Pas (low viscous set)
-1.0x10-4 0.0 1.0x10-4
1
1/T-1/T0 [K-1]
η 0(T)/
η 0(T0)
Time-Temperature Superposition
8
Newtonian Solutions Non-Newtonian Solutions
T0 = 27°C
-2.0x10-4 -1.0x10-4 0.0 1.0x10-4
1
η 0(T)/
η 0(T0)
1/T-1/T0 [K-1]
Glycerol/Water (88/12 wt%) (η0 = 0.10 Pas) PEO/Water (1/99 wt%) (η0 = 0.12 Pas)
-1.0x10-4 0.0 1.0x10-4
1
η 0(T)/
η 0(T0)
1/T-1/T0 [K-1]
PEO 1wt% in Glycerol/Water (50/50 wt%) (η0 = 0.74Pas)
-1.0x10-4 0.0 1.0x10-4
1
2
η 0(T)/
η 0(T0)
1/T-1/T0 [K-1]
Pure glycerol (η0 = 0.64 Pas)
0
0
= =
==
0.0 0.5 1.0 1.5 2.01E-4
1E-3
0.01
0.1
R/R
0
time [s]
0.0 0.1 0.2 0.3 0.4 0.51E-4
1E-3
0.01
0.1
R/R
0
time [s]
1wt%PEO in Water (η0 = 0.12 Pas)
Minimum resolvable diameter ratio
CaBER Measurements
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1wt%PEO in Glycerol/Water (50/50 wt%) (η0 = 0.74 Pas)
Based on Oldroyd-B model, the onset of extensional-thickening occurs for
Extensional-thickening expected whenFor 1wt%PEO in Water
For 1wt%PEO in Glycerol/water (50/50 wt%)
Minimum resolvable diameter ratio
10-1 100 101 102 103 104 105
10-2
10-1
100
101
Operating Enveloppe ARES Operating Enveloppe ARES-G2
η E [P
as]
dε/dt [s-1]
• Even for Newtonian solutions,
probably due to dynamic pressure and shear in the nozzles
ARES-G2 Measurements with Newtonian Fluids
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Expulsion mode, Nozzle diameter = 0.84 mm, T = 27°C
Pure glycerol
3η0 = 1.92 Pa s
3η0 = 0.30 Pa s
Glycerol/Water (88/12 wt%)
• The increase in the apparent extensional viscosity due to liquid inertia is more visible at higher extension rates
Inertia correction*
*
Tests with Smaller Nozzle Diameter
1110 100 1000 10000
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.80.9
1
ARES-G2 (nozzle diameter=0.84mm) expulsion 3η
0= 0.3 Pas
ARES (nozzle diameter=0.51mm) expulsion ARES (nozzle diameter=0.51mm) suction ARES-G2 (nozzle diameter=0.84mm) suction
dε/dt [s-1]
η E [P
as]
Onset of Cavitation
Glycerol/Water (88/12 wt%) (η0 = 0.10 Pas)
T = 27°C
• The data at higher extension rates confirm the increase in the apparent extensional viscosity due to inertia
• Cavitation issues must be solved to observe the effect of inertia for the suction mode
• The onset of extensional thickening based on the CABER relaxation time is not experimentally observed, probably due to the fact that the strain experienced by a fluid element is not sufficient :
• For this low constant strain, the strain hardening phenomenon is expected to be small. However, it could be possible to observe it by going to higher extension rates.
10-1 100 101 102 103 104 105
10-2
10-1
100
101
102
Enveloppe ARES-G2 Enveloppe ARES
dε/dt [s-1]
η E [P
as]
ARES-G2 Measurements with Non-Newtonian Fluids
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Expulsion mode, Nozzle diameter = 0.84 mm, T = 27°C
PEO 1wt% in (Glycerol/Water) (50/50 wt%)
3η0 = 2.22 Pa s
PEO/Water (1/99 wt%)3η0 = 0.35 Pa s
Inertia correction*
*
for
1 10 100 10000.1
1
10
100
Expulsion Suction
dε/dt [s-1]
η E [P
as]
Suction mode with Non-Newtonian Fluids
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Expulsion mode (□) and suction mode (○), Nozzle diameter = 0.84 mm, T = 27°C
PEO 1wt% in (Glycerol/Water)
(50/50 wt%)
3η0 = 2.22 Pa s
PEO/Water (1/99 wt%)
3η0 = 0.35 Pa s
Onset of Cavitation
Onset of Cavitation
Onset of extensional thickening
Onset of extensional thickening
• Significant discrepancy between the two modes
• Extensional thickening is observed in suction mode (stretching) but not in expulsion (compression)
• Cavitation starts at lower extension rates for more viscous solutions
10 100 1000 100000.1
1
10
dε/dt [s-1]
η E [P
as]
Suction mode : Comparison Newtonian/Non-Newtonian
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Suction mode, Nozzle diameter = 0.84 mm, T = 27°C
PEO/Water (1/99 wt%)
3η0 = 0.35 Pa s
Onset of Cavitation
Onset of extensional thickening • Extensional thickening is observed
in suction mode for the non-Newtonian solution but not for the Newtonian counterpart
• Cavitation starts at lower extension rates for the non-Newtonian solution, which is more viscous
Glycerol/Water (88/12 wt%)
3η0 = 0.30 Pa s
Onset of Cavitation
10 100 10000.1
1
10
100
3η0= 1.92 Pas
ARES Expulsion RFX Expulsion RFX Suction ARES Suction
dε/dt [s-1]
η E [P
as]
Comparison with RFX Data : Newtonian Solutions
10 100 1000 100000.1
1
10
100
3η0= 0.30 Pas
ARES Expulsion ARES Suction RFX Expulsion RFX Suction
dε/dt [s-1]
η E [P
as]
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Glycerol/water (88/12 wt%) (η0 = 0.10 Pas) Pure Glycerol (η0 = 0.64 Pas)
T = 27°C T = 27°C
Good agreement with RFX data
Comparison with RFX Data : Non-Newtonian Solutions
10 100 10000.1
1
10
100
ARES Expulsion ARES Suction 3η
0= 0.35 Pas
RFX Expulsion RFX Suction
η E [P
as]
dε/dt [s-1]
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1wt%PEO in Water (η0 = 0.12 Pas) 1wt%PEO in Glycerol/water (50/50 wt%) (η0 = 0.74 Pas)
10 100 10000.1
1
10
100
3η0= 2.22 Pas
ARES Expulsion ARES Suction RFX Expulsion RFX Suction
η E [P
as]
dε/dt [s-1]
T = 27°C T = 27°C
Suction mode : increase of ηE : extensional-thickening confirmed by the RFX dataExpulsion mode : increase of ηE at higher rates : extensional-thickening ?
10 100 1000 100000.1
0.2
0.3
0.4
0.5
0.6
0.7
0.80.9
1
dε/dt [s-1]
η E [P
as]
T = 24°C
KI = 0.7
KI = 0.2
3η0 = 0.28 Pa s
Expulsion
Suction
Tests with New Tubing
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Glycerol/Water (88/12 wt%) (η0 = 0.09 Pas)
• Expulsion mode : the increase of ηE at higher extension rate is well captured with an inertia correction coefficient KI = 0.7
• Suction mode : cavitationissues are solved and ηE also increases but with a smaller coefficient KI = 0.2
• At lower extension rates :
101 102 103 104
10-1
100
Expulsion new tubing Suction new tubing Expulsion old tubing Suction old tubing
η E [P
as]
dε/dt [s-1]
1wt% PEO in Water (η0 = 0.12 Pas)
T = 24°C
Tests with New Tubing
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• Expulsion mode : the increase of ηE is well captured with an inertia correction coefficient of KI = 0.70, which is in agreement with that of the Newtonian fluid counterpart
• Suction mode : the extensional-thickening and cavitation are still observed
• The decay of ηE at lower extension rates has not been completely eliminated : there probably still exists a shear contributionKI = 0.7
3η0 = 0.45 Pa s Expulsion
Suction
-2.0x10-6 -1.0x10-6 0.00.0
1.0x10-4
2.0x10-4
3.0x10-4
4.0x10-4
5.0x10-4
6.0x10-4
7.0x10-4
Min
ertia
[Nm
]
Q [m3s-1]0.0 1.0x10-6 2.0x10-6
0.0
1.0x10-5
2.0x10-5
3.0x10-5
4.0x10-5
5.0x10-5
6.0x10-5
MIn
ertia
[Nm
]
Q [m3s-1]
Inertia Correction : KI measured (KIm) with one single nozzle
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Expulsion/Suction in immersion with one single nozzle at 24°C
Suction KIm ≈ 0.2Expulsion KIm≈ 2.2
According to Dontula’s notations :
Water (0.51mm)KIm=2.2
Water (0.51mm) KIm=0.1Gly/H2O (88/12 wt%)
(0.84mm) KIm=2.2
Gly/H2O (88/12) (0.84mm) KIm=0.3
Water (0.84mm) KIm=2.3
Water (0.84mm) KIm=0.2
100 1000 100000.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
dε/dt [s-1]
η E [P
as]
T = 24°C
KI = 0.7
KI = 0.2
3η0 = 0.28 Pa s
Expulsion
Suction
Inertia Correction : Comparison of KI and KIm
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Glycerol/water (88/12 wt%) (η0 = 0.09 Pas)
KIm = 0.2
KIm = 2.2 • Another contribution decreasing the apparent extensional viscosity during the inertia measurement ?
with
• Suction mode :
• Expulsion mode :
→ Wall effect ?
• Inertia calibration: different correction coefficients in suction and expulsion
• Measured inertia coefficients and sign different from those proposed by Dontula
• Good agreement with RFX results for the Newtonian and viscoelastic solutions
• Extensional-thickening observed only in suction mode
Conclusions
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• At lower extension rate :
• Cavitation issues in suction mode solved by using shorter tubing
• Flexibility of the fixture that can be mounted on ARES-G2 or ARES
As good as original RFX
Better than original RFX
Expulsion : Suction :
Acknowledgments
• Dr. Johannes Soulages
• Prof. Gareth H. McKinley, MIT
• Jürg Hostettler, ETH Zürich
• Russell Ulbrich, TA Instruments
• Aadil Elmoumni, TA Instruments
• Sujit S. Datta, Harvard University
• Prof. David Weitz, Harvard Univeristy
• David Gilles, University of Minnesota
• Prof. Christopher W. Macosko, University of
Minnesota
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