An idealized centrifugal pump (blade outer radius of 50 mm) consumes 2 kW power while running at 3000 rpm

Q. An idealized centrifugal pump (blade outer radius of 50 mm) consumes 2 kW power while running at 3000 rpm. The entry of the liquid into the pump is axial and exit from the pump is radial with respect to impeller. If the losses are neglected, then the mass flow rate of the liquid through the pump is  kg/s (round off to two decimal places).

Ans: 8.11 kg/s

Sol:

D = 2 x 50 = 100 mm
N = 3000 rpm.
Power, P = m.u²

= 15707.963 mm/sec.
= 15.7079 m/sec.
⇒ 2000 = m(15.7079)²
⇒ m8.105 kg/s ≈ 8.11 kg/s