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3B2 - Ultimate ABSA Study Guide C1-15
Questions and Correct Answers
Turbine nozzles convert heat energy into:
a. Potential energy.
b. Enthalpy.
c. Eddy-currents.
d. Kinetic energy.
e. Pressure. Ans: — D
Labyrinth seals are:
1. Made of cast iron.
2. A positive leak-proof seal arrangement.
3. Design to have large clearances between the shaft and casing.
4. Made of brass or stainless steel.
5. Used on larger diameter turbine shafts.
a. 1, 2.
b. 2, 4, 5.
c. 3, 4, 5.
d. 4, 5.
e. 1, 2, 3. Ans: — D
Flange warming on a steam turbine decreases:
a. Creep.
b. Start up time.
c. Movement.
d. Radiation losses.
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e. Noises. Ans: — B
In pressure compound steam turbines:
1. The expansion of steam from boiler pressure to exhaust
pressure is carried out in a number of steps or stages.
2. Each stage has a set of nozzles and a row of blades.
3. All of the velocity available is developed in one set of nozzles.
4. Rows of moving blades are separated by partitions or
diaphragms into which nozzles have been installed.
a. 1,2,3.
b. 2,3,4
c. 1,3,4
d. 2,4
e. 2,3,4. Ans: — D
In a/an _____ turbine there is a difference in pressure across the
_____ blades. Therefore the steam will tend to _____ around the
periphery of the blades instead of passing through them.
1. Impulse.
2. Moving.
3. Reaction.
4. Drip.
5. Stationary.
6. Leak.
a. 1,2,4.
b. 3,5,6.
c. 3,2,6.
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d. 1,5,4.
e. 1,5,6. Ans: — C
The pressure at the outlet from the moving blades is the same as
the pressure at the inlet to the moving blades in a/an turbine.
a. Topping.
b. Reaction.
c. Back pressure.
d. Impulse.
e. Extraction. Ans: — D
When disc rotors are assembled, the discs are heated until they are
easily slid along the shaft and then located in the correct position
on the shaft and shaft key. A small clearance between the discs
prevents:
a. Noise.
b. Slippage.
c. Thermal stress in the shaft.
d. Acceleration.
e. Vibration. Ans: — C
In an impulse steam turbine nozzle the following events take
place:
1. Steam pressure decreases
2. Enthalpy of the steam decreases
3. Velocity of the steam increases
4. Volume of the steam increases
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a. 1,2,4
b. 1,3,4
c. 2,3,4
d. 1,2,3
e. 1,2,3,4 Ans: — E
A turbine that expands the steam in two or more sets of nozzles in
series, each set having velocity-compounded blades to receive the
steam issuing from the nozzles is called a/an:
a. Extraction turbine.
b. Velocity compounded turbine.
c. Pressure compounded turbine.
d. Pressure-velocity compounded turbine.
e. Mixed-pressure turbine. Ans: — D
In a back-pressure turbine the process steam pressure is:
a. Kept constant and the generator output depends on the demand
for process steam.
b. Varied and the generator output remains constant.
c. Kept constant and the generator output remains constant.
d. Not important.
e. Dependant on the generator output. Ans: — A
Extraction turbines are turbines where steam is extracted at one or
more points at constant:
a. Flow.
b. Pressure.
c. Load.
d. Temperature.
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3B2 - Ultimate ABSA Study Guide C1-15
Questions and Correct Answers
Turbine nozzles convert heat energy into:
a. Potential energy.
b. Enthalpy.
c. Eddy-currents.
d. Kinetic energy.
e. Pressure. Ans: — D
Labyrinth seals are:
1. Made of cast iron.
2. A positive leak-proof seal arrangement.
3. Design to have large clearances between the shaft and casing.
4. Made of brass or stainless steel.
5. Used on larger diameter turbine shafts.
a. 1, 2.
b. 2, 4, 5.
c. 3, 4, 5.
d. 4, 5.
e. 1, 2, 3. Ans: — D
Flange warming on a steam turbine decreases:
a. Creep.
b. Start up time.
c. Movement.
d. Radiation losses.
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, 2 | Page
e. Noises. Ans: — B
In pressure compound steam turbines:
1. The expansion of steam from boiler pressure to exhaust
pressure is carried out in a number of steps or stages.
2. Each stage has a set of nozzles and a row of blades.
3. All of the velocity available is developed in one set of nozzles.
4. Rows of moving blades are separated by partitions or
diaphragms into which nozzles have been installed.
a. 1,2,3.
b. 2,3,4
c. 1,3,4
d. 2,4
e. 2,3,4. Ans: — D
In a/an _____ turbine there is a difference in pressure across the
_____ blades. Therefore the steam will tend to _____ around the
periphery of the blades instead of passing through them.
1. Impulse.
2. Moving.
3. Reaction.
4. Drip.
5. Stationary.
6. Leak.
a. 1,2,4.
b. 3,5,6.
c. 3,2,6.
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d. 1,5,4.
e. 1,5,6. Ans: — C
The pressure at the outlet from the moving blades is the same as
the pressure at the inlet to the moving blades in a/an turbine.
a. Topping.
b. Reaction.
c. Back pressure.
d. Impulse.
e. Extraction. Ans: — D
When disc rotors are assembled, the discs are heated until they are
easily slid along the shaft and then located in the correct position
on the shaft and shaft key. A small clearance between the discs
prevents:
a. Noise.
b. Slippage.
c. Thermal stress in the shaft.
d. Acceleration.
e. Vibration. Ans: — C
In an impulse steam turbine nozzle the following events take
place:
1. Steam pressure decreases
2. Enthalpy of the steam decreases
3. Velocity of the steam increases
4. Volume of the steam increases
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a. 1,2,4
b. 1,3,4
c. 2,3,4
d. 1,2,3
e. 1,2,3,4 Ans: — E
A turbine that expands the steam in two or more sets of nozzles in
series, each set having velocity-compounded blades to receive the
steam issuing from the nozzles is called a/an:
a. Extraction turbine.
b. Velocity compounded turbine.
c. Pressure compounded turbine.
d. Pressure-velocity compounded turbine.
e. Mixed-pressure turbine. Ans: — D
In a back-pressure turbine the process steam pressure is:
a. Kept constant and the generator output depends on the demand
for process steam.
b. Varied and the generator output remains constant.
c. Kept constant and the generator output remains constant.
d. Not important.
e. Dependant on the generator output. Ans: — A
Extraction turbines are turbines where steam is extracted at one or
more points at constant:
a. Flow.
b. Pressure.
c. Load.
d. Temperature.
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