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Q5. Steam at a rate of 2 kg/s flows through a single row impulse turbine which has a mean blade ring diameter of 956 mm and runs at 4000 rev/min.

The nozzles are set at 250 to the plane of rotation and reduce the specific enthalpy of the steam by 320 kJ/kg.

The blades have a velocity coefficient of 0.8 with inlet and outlet angles selected to give zero axial thrust.

(a) Draw the steam velocity vector diagram to a scale of 1 mm = 5 m/s. (5)

(b) Determine EACH of the following:

(i) the blade inlet and outlet angles; (3)

(ii) the driving force on the blades; (3)

(iii) the diagram power; (2)

(iv) the diagram efficiency. (3)