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Q5. A vector diagram on graph sheet is available

The first stage of an impulse turbine is velocity compounded with two rows of moving blades. The enthalpy drop in the nozzles is 198.5 kJ/kg.

The steam leaves the nozzles at an angle of 20° to the plane of blade rotation and the mean blade speed is 100 m/s.

The axial velocity of the steam remains constant throughout the stage.

A blade velocity coefficient of 0.9 may be assumed for all the blade rows.

(a) Draw the steam velocity vector diagram to a scale of 1 mm = 5 m/s (6)

(b) Determine EACH of the following:

(i) the blade angles for each row of moving blades; (2)

(ii) the blade angle for the fixed blades; (2)

(iii) the absolute velocity of the steam leaving the stage; (2)

(iv) the diagram power output for 1 kg's of steam flow; (2)

(v) the diagram efficiency. (2)