rheology of particle-foam mixture - sfb...

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Interaktionsmodelle maschineller Tunnelbau

SFB 837 Rheologie – Workshop 04. Juni 2014

Rheology of Particle-Foam Mixture

Aycan Özlem Özarmut

Holger Steeb


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TP | A4 Rheology of Foam

2Rheology of Particle-Foam Mixture

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TP | A4 Foam in EPB Tunneling


Improvement of the fluidity and watertightness of excavated soilTo prevent the soil from sticking inside of the chamberEasy transportation of excavated soil

[Herrenknecht AG]


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TP | A4 Objectives & Motivation

Objectives

Experimental research on constitutive properties of face support material

Understanding the rheology of foam and particle laden foam

Motivation

Determination of rheological parameters on realistic scale not possible

Investigation of rheological experiments on micro-scale

Replacing realistic support material by model material (shaving foam and glass beads)


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TP | A4 Micro-scale investigation

Micro-scale characterization through imageanalysis

Rheological characterization


liquid foamdry glass beads

+foam

wetted glass beads+

foam


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TP | A4 Micro-scale characterization

Mean diameter (D)

Cell size distribution

Shaving foam

Silibeads glassbeads Type S


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Solid glass beads + shaving foam

30% volume of solid glass beads

After 2 min. (left) and 57 min. (right)

Aging of foams

Coalescence Coarsening Drainage


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Wetted glass beads + shaving foam

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Wetted solid glass beads + shaving foam

64 % volume of wetted solid glass beads

55% volume of solid glass beads

After 1 min. (left) and 1 hour (right)


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TP | A4 Types of Rheological Systems


MCR 301 (Anton paar GmbH)

plate-plate cone-plate concentric cylinder

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TP | A4 Basic Rheological Tests


Flow curve test: Aplication of shear rate: measure stress response

Creep test: Application of constant stress: measuredeformation response

0scillation test (AS & FS): Apply strain rate oscillations, measure stress response

Relaxation test: Apply constant strain, measure decay in modulus

Ramp: Increase shear rate, measure stress increase


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TP | A4 Rheological Experiments


flow curve

oscillation test (AS & FS)

relaxation test

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SFB 837

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TP | A4 Rheological Experiments


slip effect:

disrupts the continuity of flow

resulting shear stress are reduced

to minimize slip effect:

rough plate surfaces

-sand paper : P320 (very fine)

Sandpaper

M


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TP | A4 Rheological characterization


Liquid foamdry particle mixture

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TP | A4 Flow curve experiment

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Herschel Bulkley Papanastasiou model:

Fitting parameter from Herschel Bulkley Papanastasiou model:

Case 1

Case 7

Volume fraction of liquid foam-dry particle mixture:



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Herschel-Bulkley Papanastasiou model:

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TP | A4 Constitutive equation

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Generalized incompressible Fluids:


Fluids:

(Constitutive relation)Cauchy stress

rate of deformation tensor

viscosity

unity tensor

Measuring constraints of rheometry:

The flow is fully described by the continuity equation

The fluid flow laminar and isothermal and steady state

Its density is constant

No slippage on the wall


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TP | A4 Constitutive equation

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Plane Couette flow or simple shear:


Velocity gradient:v1

x

1

x

2

fluidH

Rate of Deformation tensor: Second invariant of strain tensor :

Viscosity & Shear stress in 3D:

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TP | A4 Amplitude & Frequancy sweep


Amplitude sweepSmall amplitude oscillatory sweep (SAOS)Large amplitude oscillatory sweep (LAOS)


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TP | A4 Amplitude sweep (SAOS)


Case 1

Case 7

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SFB 837

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TP | A4 Rheological characterization


Liquid foam- wetted particle mixture

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Herschel Bulkley Papanastasiou model:

Volume fraction of liquid foam-wetted particle mixture:

Case 4

Case 1


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Volume fraction of wetted particles from down to up: 0, 0.09, 0.16, 0.23 , 0.28, 0.33, 0.41, 0.47, 0.54, 0.6, 0.64, 0.7 and 0.8

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Volume fraction of wetted particles : 0, 0.09, 0.23, 0.33, 0.54, 0.6, 0.64


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TP | A4 Amplitude sweep (LAOS)


The four archetypes of LAOS behavior (Hyun et al., Rheol Acta 2006 ) :(a) strain thinning (b) strain hardening(c) weak strain overshoot (d) strong strain overshoot

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TP | A4 Relaxation test


strain-time and stress-time curve with different material behavior :


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TP | A4 Conclusion


Aging of foam (coalescence, coarsening, drainage) in a period of time was observed

Foam and particle-foam mixture can be characterised by Herschel-BulkleyPapanastasiou model

The yield stress function should be improved

Material property depends on composition of particle-foam mixture

Over 0.30 volume of particles results in noisy data for flow curve test

Linear and non-linear regions of particle-foam mixture were obtained byamplitude sweep test

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TP | A4


Thank you for your attention !

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rheology of particle-foam mixture - sfb...

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