238
M. Gleiss and H. Nirschl
E(D) Residence time distribution function [−]
E
Separation efficiency [−]
F(D) Residence time distribution [−]
G
Grade efficiency [−]
h
Hindered settling factor [−]
L cyl
Length of the cylindrical drum [m]
L hel
Length of the unrolled screw channel [m]
˙
m s,i - 1 Incoming mass flow of solids [kg s
−1 ]
˙
m s,i
Outgoing mass flow of solids [kg s
−1 ]
˙
m s,sep Mass flow of separated solids [kg s
−1 ]
N
Total number of compartments [−]
n RZ
Exponent Richardson and Zaki [−]
p 1
Empirical parameter for solids pressure function [Pa]
p 2
Empirical parameter for solids pressure function [−]
p s
Solids pressure [Pa]
P
Product loss [−]
q 3,i
Mass density distribution [m
−1 ]
Q
Volumetric flow rate [m
3 s
−1 ]
r 1 , r 2 Empirical parameters for hindered settling function [−]
R d
Radius of the bowl [m]
R m
Mean radius of the bowl [m]
R max Maximum radius of the sediment [m]
R s
Radius of sediment surface [m]
R w
Radius of the weir [m]
Re p
Particle Reynolds number [−]
S dyn
Normalized dynamic change [−]
t
Time [s]
T
Transport efficiency [−]
x
Particle diameter [m]
x 50,3 Mean particle diameter dependent on mass [m]
U
Volumetric Filling level [−]
U max Maximum volumetric filling level [−]
V hel
Volume of the screw channel in the cylindrical part of the decanter centrifuge
[m
3 ]
V
Volume of a compartment in the sedimentation zone [m
3 ]
V sed
Sediment volume [m
3 ]
β
Screw angle [rad]
l
Length of a compartment [m]
n
Differential speed between screw and drum [rpm]
η
Dynamic viscosity [Pa s]
φ
Solids volume fraction [−]
φ c
Mean solids volume fraction of the sediment [−]
ρ
Density [kg m
−3 ]
τ
Mean residence time [s]
ω
Angular velocity [s
−1 ]
M. Gleiss and H. Nirschl
E(D) Residence time distribution function [−]
E
Separation efficiency [−]
F(D) Residence time distribution [−]
G
Grade efficiency [−]
h
Hindered settling factor [−]
L cyl
Length of the cylindrical drum [m]
L hel
Length of the unrolled screw channel [m]
˙
m s,i - 1 Incoming mass flow of solids [kg s
−1 ]
˙
m s,i
Outgoing mass flow of solids [kg s
−1 ]
˙
m s,sep Mass flow of separated solids [kg s
−1 ]
N
Total number of compartments [−]
n RZ
Exponent Richardson and Zaki [−]
p 1
Empirical parameter for solids pressure function [Pa]
p 2
Empirical parameter for solids pressure function [−]
p s
Solids pressure [Pa]
P
Product loss [−]
q 3,i
Mass density distribution [m
−1 ]
Q
Volumetric flow rate [m
3 s
−1 ]
r 1 , r 2 Empirical parameters for hindered settling function [−]
R d
Radius of the bowl [m]
R m
Mean radius of the bowl [m]
R max Maximum radius of the sediment [m]
R s
Radius of sediment surface [m]
R w
Radius of the weir [m]
Re p
Particle Reynolds number [−]
S dyn
Normalized dynamic change [−]
t
Time [s]
T
Transport efficiency [−]
x
Particle diameter [m]
x 50,3 Mean particle diameter dependent on mass [m]
U
Volumetric Filling level [−]
U max Maximum volumetric filling level [−]
V hel
Volume of the screw channel in the cylindrical part of the decanter centrifuge
[m
3 ]
V
Volume of a compartment in the sedimentation zone [m
3 ]
V sed
Sediment volume [m
3 ]
β
Screw angle [rad]
l
Length of a compartment [m]
n
Differential speed between screw and drum [rpm]
η
Dynamic viscosity [Pa s]
φ
Solids volume fraction [−]
φ c
Mean solids volume fraction of the sediment [−]
ρ
Density [kg m
−3 ]
τ
Mean residence time [s]
ω
Angular velocity [s
−1 ]