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

Chapter 2 Literature Review Page 2.41
Although this correlation does not provide an explanation <strong>of</strong> <strong>the</strong> behaviour <strong>of</strong> <strong>the</strong> slurry in
terms <strong>of</strong> <strong>the</strong> physical properties <strong>of</strong> <strong>the</strong> slurry, it does produce a good correlation <strong>of</strong> non­
Newtonian turbulent flow pipe data (Harris & Quader, 1971 and Quader & Wilkinson, 1980).
2.12 EVIDENCE OF PARTICLE ROUGHNESS
Many researchers report similarity between <strong>the</strong> turbulent behaviour <strong>of</strong> Newtonian fluids and
non-Newtonian slurries (Caldwell & Babbitt 1941, Hedstrom 1952, Metzner & Reed 1955,
Dodge & Metzner 1959, Tomita 1959, Michiyoshi et al 1966, Edwards & Smith 1980,
Thomas & Wilson 1987 and Sive 1988). One <strong>of</strong> <strong>the</strong> more interesting pieces <strong>of</strong> evidence to
date on <strong>the</strong> similarity between Newtonian and non-Newtonian slurry turbulent flow is
presented by Park et al (1989).
Park et al (1989) investigated <strong>the</strong> turbulent structure <strong>of</strong> a non-Newtonian slurry using laser
doppler anemometry and concluded that <strong>the</strong> transition region is much narrower than for
Newtonian fluids. Their non-Newtonian slurry turbulent flow velocity pr<strong>of</strong>ile (Figure 2.16)
agrees well with measurements with air (Newtonian fluid). However, <strong>the</strong>y reported higher
relative turbulence intensities in <strong>the</strong> wall region for <strong>the</strong> slurry, when compared with air
(Figure 2.17). This would support <strong>the</strong> concept <strong>of</strong> <strong>particle</strong> roughness. Pokryvalio &
Grozberg (1995) confmned <strong>the</strong> findings <strong>of</strong> Park et al (1989) using electro-diffusion
techniques for measuring velocity pr<strong>of</strong>iles <strong>of</strong>Bentonite clay suspensions at concentrations <strong>of</strong>
4% and 6% and comparing it with air. They reported a significant increase in turbulence
intensities in <strong>the</strong> wall region for <strong>the</strong> Bentonite clay suspension (Figure 2.18), providing
fur<strong>the</strong>r support <strong>of</strong> <strong>the</strong> concept <strong>of</strong> <strong>particle</strong> roughness.
2.13 DATA FROM THE LITERATURE
Experimental data obtained by Sive (1988) was used in <strong>the</strong> analysis <strong>of</strong> <strong>the</strong> various models
under consideration. The tests conducted by Sive (1988) were done using a mixture <strong>of</strong>kaolin
clay and a relatively coarse quartz sand, which resulted in a heterogeneous, settling slurry.
The purpose <strong>of</strong> using this data was to see if <strong>the</strong> coarse, settling <strong>particle</strong>s contributed to <strong>the</strong>
turbulent flow headloss, as proposed by <strong>the</strong> Slatter model.