Steam Nozzles and Turbines - Section 1

Directions to Solve

Steam Nozzles and Turbines - Section 1

1.

The velocity of steam leaving the nozzle (V) is given by (where K = Nozzle coefficient or nozzle efficiency, and hd = Enthalpy or heat drop during expansion of steam in a nozzle)

A.	V = 44.72 hd
B.	V = 44.72 K
C.	V = 44.72
D.	V = 44.72 K hd

Answer: Option C

Explanation:

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2.

The rate of discharge through the nozzle __________ when the exit pressure is gradually reduced.

A.	remains same
B.	decreases
C.	increases

Answer: Option C

Explanation:

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3.

The discharge of steam in a convergent-divergent nozzle __________ after the throat (i.e. in the divergent portion of the nozzle)

A.	remains constant
B.	decreases
C.	increases

Answer: Option A

Explanation:

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4.

The pressure at which the steam leaves the nozzle is known as back pressure.

A.	Correct
B.	Incorrect

Answer: Option A

Explanation:

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5.

The ratio of total useful heat drop to the total isentropic heat drop, is called

A.	stage efficiency
B.	internal efficiency
C.	Rankine efficiency
D.	none of these

Answer: Option B

Explanation:

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6.

The flow through a nozzle is regarded as

A.	constant volume flow
B.	constant pressure flow
C.	isothermal flow
D.	isentropic flow

Answer: Option D

Explanation:

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7.

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.	60°
B.	90°
C.	180°
D.	270°

Answer: Option B

Explanation:

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8.

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

Answer: Option B

Explanation:

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