Abstract
The flocculation of particles in a liquid depends on collisions between particles, caused by their relative motion. This relative motion may be caused by Brownian movement, by fluid movement giving rise to velocity gradients, or by particle motion due to an external force (e.g. gravity).
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Abbreviations
- d:
-
centre to centre distance between particles
m
- Di :
-
diffusion coefficięnt for i-particle
m s2-1
- g:
-
gravitational acceleration 9.81
m s-2
- G:
-
velocity gradient
s-1
- i:
-
label for particle of the ith kind
−
- j:
-
label for particle of the jth kind
−
- k:
-
label for particle formed by aggregation of i- and j-particles
−
- KB :
-
Boltzmann’s constant 1.38 x 10-23
J K-1
- L:
-
arc distance of a small sector of liquid undergoing rotational shear
m
- Ni :
-
number of i-particles per unit volume
m-3
- Nj :
-
number of j-particles per unit volume
m-3
- NK :
-
number of k-particles per unit volume
m-3
- NO :
-
initial (t=o) number of particles per unit volume
m-3
- Nt :
-
total number of particles per unit volume at time t
m-3
- p:
-
label for particles of a size limited by shear
−
- P:
-
power dissipated in fluid motion
W
- Q:
-
liquid flow due to velocity gradient
m s3-1
- r:
-
radial distance from the centre of a collector
m
- ri :
-
radius of an i-particle
m
- rj :
-
radius of an j-particle
m
- R:
-
radius of a small sector of liquid in rotational shear
m
- Rij :
-
radius of interaction of i- and j-particles
m
- s:
-
distance term in potential energy function
−
- t:
-
time of flocculation
s
- T:
-
absolute temperature
K
- u:
-
local liquid velocity
m s-1
- vi :
-
Stokes’ velocity of an i-particle
m s-1
- vj :
-
Stokes’ velocity of an j-particle
m s-1
- V:
-
liquid volume
m3
- Vi :
-
volume of an i-particle
m3
- Vs :
-
potential energy at distance s
J
- x:
-
co-ordinate distance along streamline through centre of j-particle
m
- y:
-
co-ordinate distance
m
- z:
-
co-ordinate distance across velocity gradient
m
- α:
-
collision efficiency
- θ:
-
angle of rotation of a small sector of liquid
rad
- μ:
-
dynamic viscosity of liquid
kg m-1 s-1
- P:
-
density of liquid
kg m-3
- Pi :
-
density of i-particles
kg m-3
- Ps :
-
density of floc particles
kg m-3
- Ï„:
-
shear stress in liquid
N m-2
- φ:
-
floc volume per unit liquid volume
References
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Harris, H.S., Kaufmann, W.J. and Krone, R.B., Orthokinetic flocculation in water purification, J. San. Eng. Div., Proc. Am. Soc. Civ. Engrs., 92,(SA6), 95, 1966.
Ives, K.J. and Bhole, A.G., Theory of flocculation for continuous flow system, J. Env. Eng. Div., Proc. Am. Soc. Civ. Engrs., 99,(EE1), 17, 1973.
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© 1978 Sijthoff & Noordhoff International Publishers B.V.
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Ives, K.J. (1978). Rate Theories. In: Ives, K.J. (eds) The Scientific Basis of Flocculation. NATO Advanced Study Institutes Series, vol 27. Springer, Dordrecht. https://doi.org/10.1007/978-94-009-9938-1_3
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DOI: https://doi.org/10.1007/978-94-009-9938-1_3
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