Brochure

Symbol Definition Unit
POWER
P Power [W]
P
1
Power added from the electricity
supply network [W]
P
2
Power added from motor [W]
P
hyd
Hydraulic power transferred to
the fluid [W]
P
loss,{loss type}
Power loss in {loss type} [W]
SPEED
w Angular frequency [1/s]
f Frequency [Hz]
n Speed [1/min]
VELOCITIES
V The fluid velocity [m/s]
U The impeller tangential velocity [m/s]
C The fluid absolute velocity [m/s]
W The fluid relative velocity [m/s]
SPECIFIC NUMBERS
Re Reynold’s number [-]
n
q
Specific speed
FLUID CHARACTERISTICS
r The fluid density
[kg/m
3
]
n Kinematic viscosity of the fluid [m
2
/s]
MISCELLANEOUS
f Coecient of friction [-]
g Gravitational acceleration [m/s
2
]
z Dimensionless pressure loss coecient [-]
General indices
Index Definition Examples
1, in At inlet, into the component A
1
, C
in
2, out At outlet, out of the component A
2
, C
out
m Meridional direction C
m
r Radial direction W
r
U Tangential direction C
1U
a Axial direction C
a
stat Static p
stat
dyn Dynamic p
dyn
, H
dyn,in
geo Geodetic p
geo
tot Total p
tot
abs Absolute p
stat,abs
, p
tot,abs,in
rel Relative p
stat,rel
Operation Operation point Q
operation
List of Symbols
Symbol Definition Unit
FLOW
Q Flow, volume flow [m
3
/s]
Q
design
Design flow [m
3
/s]
Q
impeller
Flow through the impeller [m
3
/s]
Q
leak
Leak flow [m
3
/s]
m Mass flow [kg/s]
HEAD
H Head [m]
H
loss,{loss type}
Head loss in {loss type} [m]
NPSH Net Positive Suction Head [m]
NPSH
A
NPSH Available
(Net Positive Suction Head available
in system) [m]
NPSH
R
, NPSH
3%
NPSH Required
(The pump’s net positive suction
head system demands)
[m]
GEOMETRIC DIMENSIONS
A Cross-section area [m
2
]
b Blade height [m]
b Blade angle [
o
]
b’ Flow angle [
o
]
s Gap width [m]
D, d Diameter [m]
D
h
Hydraulic diameter [m]
k Roughness [m]
L Length (gap length, length of pipe) [m]
O Perimeter [m]
r Radius [m]
z Height [m]
Dz Dierence in height [m]
PRESSURE
p Pressure [Pa]
∆p Dierential pressure [Pa]
p
steam
The fluid vapour pressure [Pa]
p
bar
Barometric pressure [Pa]
p
beho
Positive or negative pressure
compared to p
bar
if the fluid is in a
closed container. [Pa]
P
loss,{loss type}
Pressure loss in {loss type} [Pa]
EFFICIENCIES
h
hyd
Hydraulic eciency [-]
h
control
Control eciency [-]
h
motor
Motor ecency [-]
h
tot
Total eciency for control,
motor and hydraulics [-]