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Vanderbilt University

Project 16FT1: Simulation, Rheology and

Efficiency of Polymer Enhanced Solutions

Ashlie Martini

University of California Merced

&

Paul Michael

Milwaukee School of Engineering

CCEFP Webinar

October 14, 2016

2

Research Strategy

Project Goal: Bridge the gap between fundamental behavior of polymer

enhanced fluids and the performance of complex fluid power systems

Hydraulic

Efficiency

Solution

Rheology

Molecular

Structure

3

Today’s PresentationNext Steps

Sept 2016: Complete dynamometer

testing of shear stable PMA - MSOE

• Fall 2016: Perform MD and rheology

tests on PIB polymer-containing

solutions – UC Merced

• Spring 2017: Test PIB polymer-

containing fluids in dyno - MSOE

Part I: Characterization of the effect

viscosity and shear stability on flow

losses for fluids with PMA additives

Part II: Development of methods to

study the effect of concentration and

polymer entanglement on viscosity of

fluids with PIB additives

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Part I: Efficiency-Rheology

Fluid ID HM46-6 HV46-5 HV46-8 HM46-7

Base Oil Group III Group III Group III Group II

4 cSt base oil 54% 54% NA

8 cSt base oil 100% 32% 32% NA

Polymer nil PMA PMA nil

Antiwear additive ZDDP ZDDP ZDDP ZDDP

• Four ISO viscosity grade 46 antiwear hydraulic fluids

• Zinc-based antiwear additive

• Two straight-grade fluids with Newtonian viscosity characteristics

• HM46-6 and HM46-7

• Two multigrade fluids with non-Newtonian viscosity characteristics

• HV46-5 and HV46-8

• Same ratio of 4cSt and 8cSt Group III base oils

• Different polyalkylmethacrylate (PAMA) polymers

• Low shear stability and high shear stability

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Fluid Viscosity

HV46-5 HV46-8

Multi-grade, PMA

Additive

HM46-6

Straight-grade,

no PMA

ASTM D2196-15: Standard Test

Methods for Rheological Properties of

Non-Newtonian Materials by Rotational

Viscometer

6

Shear Stability

ASTM D5621 - Standard

Test Method for Sonic

Shear Stability of

Hydraulic Fluids

Fluid ID Method HM46-6 HV46-5 HV46-8 HM46-7

Kin Vis 40C, cSt D445 before shear 44.63 49.00 49.35 47.42

Kin Vis 40C, cSt D5621 after shear 44.39 42.78 44.84 46.85

Kin Vis 100C, cSt D445 before shear 7.39 10.56 9.89 7.09

Kin Vis 100C, cSt D5621 after shear 7.36 8.85 8.90 7.05

Vis Loss, % Change at 100C 0.4 16.2 10.0 0.6

UCM Abs Vis 40C, mPa*s rheometer 37.46 40.91 41.49

UCM Abs Vis 100C, mPa*s rheometer 5.60 8.15 7.66

UCM Kin Vis 40C, cSt rheometer 44.19 48.16 48.76

UCM Kin Vis 100C, cSt rheometer 6.89 10.01 9.40

Density, g/ml 15C pycnometer 0.8477 0.8496 0.8510 0.8617

Density, g/ml 40C pycnometer 0.8308 0.8333 0.8341 0.8456

Density, g/ml 70C pycnometer 0.8125 0.8146 0.8151 0.8275

Density, g/ml 100C pycnometer 0.7940 0.7957 0.7963 0.8093

100 C

16.2%

10.0%

formulators.dynavis.com

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Motors: Danfoss Series 90Modified ISO 4392-11000 to 4000 psi

Pump: Danfoss Series 45Modified ISO 4409Axial piston pumpVariable displacement800, 1200, and 1800 rpm50⁰C and 80⁰C inlet temp

Simulate – Polymer solutions under conditions of varying temperature, pressure and shear

Formulate – Synthetic and conventional hydraulic fluids

Evaluate – Fluids in the pumps, motors, rheometers and tribometers

Model – Model pump leakage flow and motor torque losses

Dynamometer

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Circuit Schematic

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HM46-6 vs HV46-5 HM46-7 vs HV46-8

Effect of Pressure

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HM46-6 vs HV46-5 HM46-7 vs HV46-8

Mean Flow Loss

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Effect of Shear Stability

HM46-6 vs HV46-5 HM46-7 vs HV46-8

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Relevance of Shear Stability

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Viscosity and Flow Loss

Correlation: 0.63

Correlation: 0.60

HV46-5

HV46-8

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Part I Summary

• The ASTM D5621 sonic shear test provided a good indication of

the initial rate of permanent viscosity loss for PAMA containing

multigrade oils

• There appears to be a weak correlation between permanent

viscosity loss and system flow losses

Hydraulic

Efficiency

Solution

Rheology

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Part II: Rheology-Molecules

Initial Objectives:

• Characterize the effect of molecular weight and partially validate model

• Explore the effect of entanglement on VM-induced thickening

Test Fluids:

• Additive: Polyisobutylene (PIB)

• Base Oil: PAO 2

Goal:

• Correlate molecular structure of

viscosity modifiers to viscous

properties of additive-basestock blend

Solution

RheologyMolecular

Structure

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Polymers

PIB 4000

PIB 1300

PIB 2500

PIB1300 PIB2500 PIB4000

# of Repeat Units 24 45 72

Molecular Weight (g/mol) 1348.61 2526.88 4041.79

Model of three different

molecular weight polymers

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Model Systems

• 43 PAO2

• 2.4 X 2.4 X 4.8 nm3

• 80 PAO2

• 3.0 X 3.0 X 6.0 nm3

2 nm 2 nm 2 nm

• 129 PAO2

• 3.49 X 3.49 X 6.99 nm3

PIB1300

PIB2500

PIB4000All models at 10 wt.%

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Calculating Viscosity

η(λ) =η0

[1 + (λγ)2]p

Carreau

Equation

η0

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Viscosity ResultsPIB1300 PIB2500

PIB4000 PAO

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Partial Validation

www.ineos.com

Kin

em

atic V

isco

sity (

cS

t)

Measurements for direct comparison coming soon…

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Exploring Entanglement

Less viscous? More viscous?

Hypothesis: More entanglement = higher viscosity

Test models:

• Same concentration and total

PIB MW

• Entanglement possible in one

model and on the other

• Compare viscosity and degree

of entanglement

3 x PIB1300 1 x PIB4000

vs.

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Next Steps

• Characterize the effect of PIB molecular weight

• Quantify entanglement of multi-PIB models and

characterize the effect on viscosity enhancement

• Create models with different concentrations to explore

concentration effect

• Measure viscosity (rheometer) PIB-PAO2 blends at

different concentrations with different PIB molecular

weights

• Test flow loss behavior of PIB containing

fluids on dynamometer

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Thank you for your kind attention!

Thank you Pascal Society!

michael@msoe.edu

amartini@ucmerced.edu