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Q5. Steam at a pressure and temperature of 40 bar and 400°C respectively is expanded in the nozzles of a two-row velocity compounded impulse turbine to a pressure of 15 bar. The steam enters the first row of moving blades with an absolute velocity of 700 m/s. The outlet angles from the nozzles, first row of moving blades, fixed blades and the second row of moving blades are 18°, 21°, 26° and 35° respectively.

The blade velocity coefficient is 0. 9 over each of the three rows of blades. The turbine shaft speed is 3000 rev/min and the mean blade diameter is 750 mm.

(a) Determine the condition of the steam leaving the nozzles. (5)

(b) Draw the velocity diagram for each row to a scale of 1 mm = 5 m/s. (8)

(c) Determine the diagram efficiency; (3)