Pump sizing software
Pump NPSH (Android): a module in aPipeSizer
calculate NPSHa (available) and NPSHr (required) with various built-in selections including liquid vapour pressure and pipe friction losses . . .
To take a glance at all pocketEngineer software and OS requirements, click Software List.
>>> go to aPipeSizer (Android) - Pipe Sizing
Pump NPSH . . .
The following design calculations are done with Pump NPSH module in aPipeSizer.
Worked Example 1 - a pumping station (in SI units)
A pumping station with wet and dry wells arrangement is shown above.
The pump capacity is 250 l/s at 22m head. Pump RPM is 1450.
Calculate:
(a) NPSHa
(b) NPSHr
Results:
(a) NPSHa
NPSH available (NPSHa) Calculation
====================
Fluid specific gravity, SG = 1
Atmospheric pressure, Pa = 101.325 kPa
Gauge pressure in tank, Pg = 0 kPa
Absolute pressure on liquid surface, Ps = 101.325 kPa
Vapour pressure of liquid, Pv = 3.158 kPa
Height (liquid surface to pump centerline), hs = -1.583 m
Friction loss in suction pipe, hf = 0.34 m
NPSHa = 8.08 m
------------------------------
Pa = 10.329 m H2O.
Pg = 0.000 m H2O.
Ps (absolute) = 10.329 m H2O.
Pv (absolute) = 0.322 m H2O.
------------------------------
NOTE:
(1) Liquid level shall be taken at the low level condition.
(b) NPSHr
NPSH required (NPSHr) Calculation
====================
Pump speed, N = 1450 RPM
Flow rate, Q = 250 l/s
Suction specific speed, Nss = 10000
Estimated NPSHr = 5.81 m
------------------------------
NOTE:
(1) Calculated NPSHr < NPSHa. Therefore OK.
(2) Actual NPSHr shall be obtained from the selected pump curve.
From the above selected pump, actual NPSHr is approx. 4.5m < NPSHa.
Therefore OK.
NPSHa
NPSHr
Water Vapour Pressure calculator
Pump Motor KW . . .
The following design calculations are done with Pump Motor KW module in aPipeSizer.
Worked Example 2 - Pump motor KW (in SI units)
Calculate the electrical input power KW required for the pump in Example 1.
Pump motor efficiency is 80%, and motor efficiency is 92%.
Results:
Pump Motor KW Estimates
======================
Fluid specific gravity = 1
Flowrate = 250 l/s
Total head = 22 m H2O
Pump efficiency = 80 %
Shaft power = 67.40 KW
Safety factor = 0 %
Motor output = 67.40 KW
Motor efficiency = 92 %
Absorbed Power = 73.26 KW
Pump Motor KW
