the effect of the particle size distribution on non-newtonian turbulent ...

2.1 INTRODUCTION
CHAPTER 2
LITERATURE REVIEW
The presentation in this chapter deals with <strong>the</strong> rheological fundamentals relevant to fluid flow
in pipes. These fundamentals include <strong>the</strong> classification, measurement and interpretation <strong>of</strong>
non-Newtonian behaviour.
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2.2 FLOW PATTERNS
The nature <strong>of</strong> flow <strong>of</strong>a fluid depends on a number <strong>of</strong> factors. Factors influencing flow are:
• <strong>the</strong> physical properties <strong>of</strong> <strong>the</strong> fluid and its mass flow rate,
• <strong>the</strong> geometry <strong>of</strong> <strong>the</strong> container or pipeline.
The flow <strong>of</strong> a fluid can be characterized into one <strong>of</strong> three categories namely larninar flow,
transitional flow or turbulent flow.
2.2.1 L4uninar Flow
In larninar flow layers <strong>of</strong> fluid move relative to each o<strong>the</strong>r without any macroscopic
intermixing (Holland, 1973) ie. <strong>the</strong>re are no components <strong>of</strong> velocity normal to <strong>the</strong> direction
<strong>of</strong> flow (Govier & Aziz, 1972). From <strong>the</strong> above statement it can be understood why laminar
flow is also referred to as viscous or streamline flow in <strong>the</strong> literature.
For <strong>the</strong> purpose <strong>of</strong> this study <strong>the</strong> yield pseudoplastic model has been used for larninar flow
predictions (section 2.6), although o<strong>the</strong>r models in <strong>the</strong> literature may also be used.
2.2.2 Transition from Laminar to Turbulent Flow
There are several methods in <strong>the</strong> literature that can be used to identify <strong>the</strong> transition between
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