Mechanical Engineering - Steam Nozzles and Turbines

Exercise :: Steam Nozzles and Turbines - Section 3

11. 

The maximum efficiency of a De-Laval turbine is (where α = Nozzle angle)

A. sin2 α
B. cos2 α
C. tan2 α
D. cot2 α

Answer: Option B

Explanation:

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12. 

The pressure compounded impulse turbine as compared to velocity compounded turbine require __________ number of stages.

A. same
B. less
C. more

Answer: Option C

Explanation:

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13. 

In a reaction turbine when the degree of reaction is zero, then there is

A. no heat drop in moving blades
B. no heat drop in fixed blades
C. maximum heat drop in moving blades
D. maximum heat drop in fixed blades

Answer: Option A

Explanation:

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14. 

The effect of friction in the nozzle __________ dryness fraction of steam.

A. has no effect on
B. decreases
C. increases

Answer: Option C

Explanation:

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15. 

In a Parson's turbine stage, blade velocity is 320 m/s at the mean radius and rotor blade exit angle is 30°. For minimum kinetic energy of the steam leaving the stage, the steam velocity at the exit of the rotor will be

A. 160/3 m/s
B. 320/3 m/s
C. 640/3 m/s
D. 640 m/s

Answer: Option C

Explanation:

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