An axial flow pump handling oil of specific gravity 0.8 at a rate of 1.0m3 s−1 is fitted with downstream guide vanes and its impeller rotates at 250 rev min−1. The oil approaches the impeller axially,...

An axial flow pump handling oil of specific gravity 0.8 at a rate of 1.0m3 s−1 is fitted with downstream guide vanes and its impeller rotates at 250 rev min−1. The oil approaches the impeller axially, and the velocity of flow, which may be assumed constant from the hub to the tip, is 3.0ms−1. The pump consumes 60 kW, the overall efficiency being 77 per cent and the hydraulic efficiency (including guide vanes) is 86 per cent. If the impeller diameter is 0.8m and the hub diameter is 0.4 m find the inlet and outlet blade angles and the guide vane inlet angles at the hub and at the tip. Assume that the total head generated at the hub and at the tip is the same.