CALCULATION OF (NPSH)A FOR CENTRIFUGAL PUMP
Answer:
(NPSH)A =P-hfs -Pv ± Z
P(Absolute pressure)= Atmospheric Pressure+ Gauge Pressure=14.7+0=14.7PSIA=14.7*2.31=33.957 feet ≈ 34 Feet
(Tank is open to atmosphere, so Gauge pressure =0)
(1 PSIA=2.31 feet water column)
hfs (Friction losses)=3.2 Feet
Pv =0.33889PSIA=0.33889*2.31=0.783 Feet
Z= 8 feet (+8 feet due to pump is installed below reservoir)
Now (NPSH)A = 34-3.2-0.783+8=38.017 Feet ≈38 Feet
NB: All four components in the formula need to be calculated in terms of head (unit is feet in this problem)
