Background Problem

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Background Problem
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INTRODUCTION

• Flow behaviour of pastes.
• Properties quite different from those of water
  and oil (which are typical Newtonian liquids)
• Much more like toothpaste, mayonnaise or tomato
  sauce (which are typical non-Newtonian materials)
• What is solid and what is liquid?

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INTRODUCTION

• ????? ??? pantha rhei everything flows !!
• RHEOLOGY Bingham 1929
• Hookes Law elastivity ?--gt Newtons Law
  viscosity
• Visco-plastic
• Simplest models

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1.1 Newtonian Viscosity, Shear Rate, Rheogram
1.1.1 Newtons Law of Viscosity
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1.1 Newtonian Viscosity, Shear Rate, Rheogram
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1.2 Rheological Models

• Yield Pseudoplastic or Herschel-Bulkley model
• 3 constants
• Often simplified to 2 constants
• Bingham Plastic (by setting n 1)
• Power law Pseudoplastic (by setting ty 0)

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1.2 Rheological Models
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1.2 Rheological Models
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1.2 Rheological Models
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1.2 Rheological Models
SHEAR THINNING BEHAVIOUR!
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Head Loss Prediction

• Generate System Curve
• Pump/Pipe Design and Selection

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Head (m)
Water
Velocity (m/s)
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Paste
Head (m)
Water
Laminar Flow
Velocity (m/s)
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Paste
Head (m)
Water
Laminar Flow
Laminar/Turbulent Transition
Velocity (m/s)
Vc
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Paste
Head (m)
Water
Turbulent Flow
Laminar Flow
Laminar/Turbulent Transition
Velocity (m/s)
Vc
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Paste
Head (m)
Water
Turbulent Flow
Laminar Flow
!!From Ty!! Static Head
Laminar/Turbulent Transition
Velocity (m/s)
Vc
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Paste
Head (m)
Water
Turbulent Flow
Laminar Flow
Laminar/Turbulent Transition
Velocity (m/s)
Vc
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Approach

• Reynolds Number
• ?How to accommodate a material which is
• Sometimes liquid
• Sometimes solid
• Reject the solid part

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Horizontal Asymptote?? C(n) ??
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Largest Copper Mine
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2m Diameter Pumps 10 off!!
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