Q5. The first stage of an impulse turbine is a two row Curtis wheel. Steam leaves the nozzles at a velocity of 800m/s and the blade speed is 180m/s. The first row of moving blades are symmetrical with a blade angle of 30°. The outlet angles for the fixed blades and the second row of moving blades are 35° and 45° respectively.
The velocity coefficient friction is 0.85 for all the blades.
The mass flow of steam passing through the stage is 43.2 tonne/hr
(a) Draw the velocity vector diagram to the scale of 1mm = 5m/s (4)
(b) Determine each of the following:
(i) the nozzle angle (1)
(ii) the fixed blade inlet angle (1)
(iii) the 2nd row moving blade inlet angle (1)
(iv)the absolute velocity of the steam leaving the stage (1)
(c) Calculate each of the following:
(i) the power output (3)
(ii) the axial thrust (2)
(iii) the diagram efficiency (3)
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