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

Chapter 2 Literature Review Page 2.36
• Fully developed rough wall turbulent flow does exist and <strong>the</strong> partially rough
wall turbulent region is much narrower than for Newtonian fluids.
• Fully developed turbulent flow is independent <strong>of</strong><strong>the</strong> viscous characteristics <strong>of</strong>
<strong>the</strong> slurry.
• Plug flow does not occur.
In order to determine whe<strong>the</strong>r smooth wall turbulent flow or fully developed rough wall
turbulent flow exists a roughness Reynolds number was formulated in terms <strong>of</strong> <strong>the</strong> yield
pseudoplastic model.
The roughness Reynolds number is:
(2.72)
Where cl. is <strong>the</strong> representative <strong>particle</strong> <strong>size</strong>. d.=d85 was found to be good representative
<strong>particle</strong> <strong>size</strong> for <strong>the</strong> slurries tested.
If Re, < 3,32 <strong>the</strong>n smooth wall turbulent flow exists and <strong>the</strong> mean velocity is given by:
V = 2,5 In [R] -
• dgs
+ 2,5 In Re, + 1,75 .
(2.73)
If Re, > 3,32 <strong>the</strong>n fully developed rough wall turbulent flow exists and <strong>the</strong> mean velocity
is given by:
V = 2,5 In [R] -
• d85 Which reduces to
+ 4,75 ,
(2.74)