A single stage impulse turbine with a diameter of 1.2 m runs at 3000 r.p.m. If the blade speed ratio is 0.42, then the inlet velocity of steam will be
A. 79 m/s
B. 188 m/s
C. 450 m/s
D. 900 m/s
Answer C
Explanation:
v = (22/7*1.2*3000)/60 = 188.49m/s. Then, u = (188.49/.42) = 448.78 = 450 m/s.
The ratio of total useful heat drop to the total isentropic heat drop, is called
A. stage efficiency
B. internal efficency
C. Rankine efficiency
D. none of these
Answer B
The flow through a nozzle is regarded as
A. constant volume flow
B. constant pressure flow
C. isothermal flow
D. isentropic flow
Answer D
A turbine is said to have an axial discharge when the steam leaves the blade tip at __________ to the direction of the blade motion
A. 60º
B. 90º
C. 180º
D 270º
A nozzle is said to be a convergent nozzle
A. when the cross-section of the nozzle increases continuously from entrance to exit
B. when the cross-section of the nozzle decreases continuously from entrance to exit
C. when the cross-section of the nozzle first decreases from entrance to throat and then increases from its throat to exit
D. none of the above
