A centrifugal pump has an impeller with inner and outer diameter of 150 and 250 mm respectively. The pump delivers 0.05, m3/s of water when running at 1500 rev/nun. The velocity of flow through the impeller remains constraint at 2.5 m/s. The blades are curved back at an angle of 30° to the tangent at exit and the inlet is axial. The diameters of the suction and delivery pipes are 150 mm and 100 mm respectively. The pressure head at suction is 4 m below and that at delivery is, 18 m above atmosphere. The power required to drive the pump is 18 kW.
Find
(i) the vane angle at inlet
(ii) the overall efficiency, and
(iii) the manometer efficiency.