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

Chapter 1 Introduction Page lA
flow, which in turn affects <strong>the</strong> viscous sub-layer.
However, even with findings such as <strong>the</strong>se, most <strong>of</strong> <strong>the</strong> <strong>the</strong>oretical models which have been
proposed to predict turbulent flow behaviour have not taken into account <strong>the</strong> <strong>size</strong> <strong>of</strong> <strong>the</strong>
<strong>particle</strong>s inherent in <strong>the</strong> fluid. In fact Mun (1988) states that <strong>particle</strong> <strong>size</strong> is <strong>the</strong> most
frequently overlooked piece <strong>of</strong> data in published literature data. Only as recently as 1994
was a new model been proposed by Slatter (1994) to account for not only <strong>the</strong> rheology <strong>of</strong><strong>the</strong>
.
slurry but also <strong>the</strong> representative <strong>particle</strong> <strong>size</strong> <strong>of</strong> <strong>the</strong> solids.
1.2 OBJECTIVE
The aim <strong>of</strong> this study is to model turbulent flow using Slatter's model as well as o<strong>the</strong>r
models already well established in <strong>the</strong> literature, to determine <strong>the</strong> <strong>effect</strong> <strong>of</strong> <strong>the</strong> PSD on non­
Newtonian flow in pipes and to anaiyze <strong>the</strong> results.
The majority <strong>of</strong> <strong>the</strong> test work conducted by Slatter (1994) was done using kaolin clay as <strong>the</strong>
solids material with only 15 % <strong>of</strong> <strong>the</strong> tests having a representative <strong>particle</strong> <strong>size</strong> exceeding
50jLm. The average representative <strong>particle</strong> <strong>size</strong> <strong>of</strong> <strong>the</strong> remaining tests was 29JLm.
This study is essentially a continuation <strong>of</strong> work conducted by Slatter (1994) and hence tests
were conducted using kaolin clay to first confirm <strong>the</strong> accuracy <strong>of</strong> Slatter's model. Fur<strong>the</strong>r
tests were <strong>the</strong>n carried out using a mixture <strong>of</strong> kaolin clay and rock flour (mixture 1) and a
mixture <strong>of</strong> kaolin clay, rock flour and sand (mixture 2) in order to obtain a representative
<strong>particle</strong> <strong>size</strong> higher than that tested by Slatter (1994) and to observe <strong>the</strong> influence <strong>of</strong> <strong>the</strong>
<strong>particle</strong> <strong>size</strong> and <strong>the</strong> <strong>particle</strong> roughness <strong>effect</strong> on turbulent flow predictions using <strong>the</strong> various
<strong>the</strong>oretical models.