3B2 - Ultimate ABSA Study Guide test bank Chapter 1-15 |
Complete Questions and Answers 100% Correct Solutions |
Latest Update 2025
Question 1
Turbine nozzles convert heat energy into:
A) Potential energy.
B) Enthalpy.
C) Eddy-currents.
D) Kinetic energy.
E) Pressure.
Correct Answer: D) Kinetic energy.
Rationale: Turbine nozzles are designed to convert the heat (thermal)
energy and pressure energy of the steam into kinetic (velocity)
energy.
Question 2
Labyrinth seals are:
1. Made of cast iron.
2. A positive leak-proof seal arrangement.
3. Designed 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.
Correct Answer: D) 4, 5.
Rationale: Labyrinth seals are not positive leak-proof seals (they
are non-contacting, relying on flow restriction). They are
designed with small clearances to restrict flow, not large
, clearances. They are commonly made of brass or stainless
steel and are used on larger diameter turbine shafts.
Question 3
Flange warming on a steam turbine decreases:
A) Creep.
B) Start up time.
C) Movement.
D) Radiation losses.
E) Noises.
Correct Answer: B) Start up time.
Rationale: Flange warming (or gland warming) helps to equalize the
temperature across the turbine casing during startup, reducing
thermal stresses and thereby decreasing the time required to bring
the turbine up to operating speed safely.
Question 4
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.
Correct Answer: D) 2, 4
, Rationale: In pressure compound turbines, steam is expanded in
stages, with each stage having a set of nozzles and a row of
blades. Rows of moving blades are separated by diaphragms
with nozzles. All of the velocity is not developed in one set of
nozzles; rather, it is developed gradually across stages.
Question 5
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.
D) 1, 5, 4.
E) 1, 5, 6.
Correct Answer: C) 3, 2, 6.
Rationale: In a Reaction turbine there is a difference in pressure
across the moving blades. Therefore the steam will tend to
leak around the periphery of the blades instead of passing
through them.
Question 6
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.
Correct Answer: D) Impulse.
Rationale: In an impulse turbine, the pressure drop (expansion)
occurs primarily in the stationary nozzles. Therefore, the pressure
across the moving blades remains essentially constant.
Question 7
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.
Correct Answer: C) Thermal stress in the shaft.
Rationale: Providing a small clearance between the discs helps to
absorb the differential thermal expansion between the discs and the
shaft, preventing harmful thermal stress in the shaft during heating
and cooling.
Question 8
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
Complete Questions and Answers 100% Correct Solutions |
Latest Update 2025
Question 1
Turbine nozzles convert heat energy into:
A) Potential energy.
B) Enthalpy.
C) Eddy-currents.
D) Kinetic energy.
E) Pressure.
Correct Answer: D) Kinetic energy.
Rationale: Turbine nozzles are designed to convert the heat (thermal)
energy and pressure energy of the steam into kinetic (velocity)
energy.
Question 2
Labyrinth seals are:
1. Made of cast iron.
2. A positive leak-proof seal arrangement.
3. Designed 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.
Correct Answer: D) 4, 5.
Rationale: Labyrinth seals are not positive leak-proof seals (they
are non-contacting, relying on flow restriction). They are
designed with small clearances to restrict flow, not large
, clearances. They are commonly made of brass or stainless
steel and are used on larger diameter turbine shafts.
Question 3
Flange warming on a steam turbine decreases:
A) Creep.
B) Start up time.
C) Movement.
D) Radiation losses.
E) Noises.
Correct Answer: B) Start up time.
Rationale: Flange warming (or gland warming) helps to equalize the
temperature across the turbine casing during startup, reducing
thermal stresses and thereby decreasing the time required to bring
the turbine up to operating speed safely.
Question 4
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.
Correct Answer: D) 2, 4
, Rationale: In pressure compound turbines, steam is expanded in
stages, with each stage having a set of nozzles and a row of
blades. Rows of moving blades are separated by diaphragms
with nozzles. All of the velocity is not developed in one set of
nozzles; rather, it is developed gradually across stages.
Question 5
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.
D) 1, 5, 4.
E) 1, 5, 6.
Correct Answer: C) 3, 2, 6.
Rationale: In a Reaction turbine there is a difference in pressure
across the moving blades. Therefore the steam will tend to
leak around the periphery of the blades instead of passing
through them.
Question 6
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.
Correct Answer: D) Impulse.
Rationale: In an impulse turbine, the pressure drop (expansion)
occurs primarily in the stationary nozzles. Therefore, the pressure
across the moving blades remains essentially constant.
Question 7
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.
Correct Answer: C) Thermal stress in the shaft.
Rationale: Providing a small clearance between the discs helps to
absorb the differential thermal expansion between the discs and the
shaft, preventing harmful thermal stress in the shaft during heating
and cooling.
Question 8
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
