4) A centrifugal pump delivers 0.1m3/s of water at a rotational speed of 1200 rev/min. The impeller has seven vanes which lean backwards to the direction of rotation such that the vane tip angle ẞ2 is 50 deg. The impeller has an external diameter of 0.4 m, an internal diameter of 0.2m and an axial width of 31.7 mm. Assuming that the diffuser efficiency is 51.5%, that the impeller head losses are 10% of the ideal head rise and that the diffuser exit is 0.15m in diameter, estimate the slip factor, the manometric head and the hydraulic efficiency. Solution