Mechanical pumps are the second most common machine in the world (after the electric motor), so here are some of the most commonly used pumping terms and symbols.
TERMS |
SYMBOL |
UNIT |
Flowrate |
Q |
L/s |
Head |
H |
m |
Pressure |
P |
kPa |
NPSH Available |
NPSHA |
m |
NPSH Required |
NPSHR |
m |
Velocity |
V |
m/s |
Density |
ρ |
kg/m³ |
Gravitational Acceleration |
g |
m/s² |
Efficiency |
η |
– |
Rotational Speed |
N |
r/min |
Area |
A |
m² |
Absolute Viscosity |
μ |
mPa.s |
Kinematic Viscosity |
v |
mm²/s |
Specific Gravity |
S.G. |
– |
Total Dynamic Head |
HZ |
m |
Friction Head |
Hf |
m |
Static Suction Head |
Hs |
m |
Static Discharge Head |
Hd |
m |
Atmosphere Pressure Head |
Ha |
m |
Velocity Head |
Hv |
m |
Total Static Head |
Hst |
m |
Vapour Pressure Head |
Hvap |
m |
Reynolds Number |
R |
– |
Friction Factor |
f |
– |
Length of Pipe |
L |
m |
Internal Pipe Diameter |
d |
mm |
Absolute Roughness |
e |
mm |
Resistance Coefficient |
K |
– |
Total Suction Head |
Hss |
m |
Total Discharge Head |
Hds |
m |
Article courtesy of Brown Brothers Engineers Australia Pty Ltd