3B2 - CHAPTER 1: STEAM TURBINE
PRINCIPLES & DESIGN EXAM
QUESTIONS AND ANSWERS. VERIFIED
2026.
What are nozzles usually constructed of? - ANS Monel metal, formed over special dies
What is Monel? - ANS nickel-copper alloy with high tensile strength
Define 'critical pressure'. - ANS The lowest exit pressure from the nozzle that can be used
without creating turbulence.
Give the value of critical pressure. - ANS The critical pressure for a convergent nozzle occurs
when the exit pressure is 0.577 times the inlet pressure.
What nozzle is used for small pressure drops? - ANS Convergent nozzles
What nozzle is used for large pressure drops? - ANS Convergent - Divergent nozzles
What part of a convergent - divergent nozzle should be at critical pressure? - ANS nozzle
throat - narrowest part of the nozzle - outlet of the convergent section
1 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
,What are the blades in an impulse turbine reffered to as? - ANS Buckets
The buckets in an impulse turbine convert _________ energy of the steam into __________
energy. - ANS kinetic, mechanical
What are the disadvantages of an impulse turbine? - ANS -large centrigual forces due to high
rotational speeds
- large friction losses due to the high velocity of the steam
In an impulse turbine, the velocity __________ at the nozzles, then _________ in the blades. -
ANS increases, drops
-The kinetic ( velocity ) energy of the steam is transferred to the blades
In an impulse turbine, the pressure _________ in the nozzles, then __________ through the
blades - ANS Decreases, remains constant
A reaction turbine has rows of __________ blades alternating with rows of __________ blades.
- ANS stationary, moving
In a reaction turbine, what do the stationary blades act as? - ANS Due to their shape, they act
as nozzles
How are the blades in a reaction turbine characterized? - ANS large enterance angle, almost
90 degrees, and a small discharge angle
In a reaction turbine the steam pressure _________ across the stationary blades, and
_________ across the moving blades. - ANS decreases, decreases
2 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
, In a reaction turbine, the velocity _________ in the stationary blades but __________ in the
moving blades. - ANS increases, decreases
What are the disadvantages of a reaction turbine? - ANS 1. the drop in pressure across the
moving blades ecourages steam flow around the end of the blades reducing turbine efficiency
2. the difference in pressure between the inlet and outlet side of each rotor produces an axial
thrust towards the exhaust end of the turbine
In an impluse turbine, what must happen for the steam to transfer all its kentic energy to the
moving blades? - ANS The steam must leave the moving blades at the lowest possible
velocity.
The lowest velocity of the steam leaving the blades of an impulse turbine occurs when the
____________. - ANS The blade velocity is one half the steam velocity.
In an impulse turbine, what is pressure compounding? - ANS Reduces steam and blade
velocty by causing the steam pressure to drop in two or more stages. Two or more impulse
stages are used.
In an impulse turbine, what is velocity compounding? - ANS Consists of one set of sationary
nozzles, a set of moving blades, stationary blades, and moving blades to reduce the velocity.
In an impulse turbine, recuding the steam velocity in two stages results in what? -
ANS roating blades & shaft being 1/2 the speed of a simple, single stage impulse turbine
In an impulse turbine, what is pressure - velocity compounding? - ANS Reduces both steam
pressure and steam velocity in stages.
3 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
PRINCIPLES & DESIGN EXAM
QUESTIONS AND ANSWERS. VERIFIED
2026.
What are nozzles usually constructed of? - ANS Monel metal, formed over special dies
What is Monel? - ANS nickel-copper alloy with high tensile strength
Define 'critical pressure'. - ANS The lowest exit pressure from the nozzle that can be used
without creating turbulence.
Give the value of critical pressure. - ANS The critical pressure for a convergent nozzle occurs
when the exit pressure is 0.577 times the inlet pressure.
What nozzle is used for small pressure drops? - ANS Convergent nozzles
What nozzle is used for large pressure drops? - ANS Convergent - Divergent nozzles
What part of a convergent - divergent nozzle should be at critical pressure? - ANS nozzle
throat - narrowest part of the nozzle - outlet of the convergent section
1 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
,What are the blades in an impulse turbine reffered to as? - ANS Buckets
The buckets in an impulse turbine convert _________ energy of the steam into __________
energy. - ANS kinetic, mechanical
What are the disadvantages of an impulse turbine? - ANS -large centrigual forces due to high
rotational speeds
- large friction losses due to the high velocity of the steam
In an impulse turbine, the velocity __________ at the nozzles, then _________ in the blades. -
ANS increases, drops
-The kinetic ( velocity ) energy of the steam is transferred to the blades
In an impulse turbine, the pressure _________ in the nozzles, then __________ through the
blades - ANS Decreases, remains constant
A reaction turbine has rows of __________ blades alternating with rows of __________ blades.
- ANS stationary, moving
In a reaction turbine, what do the stationary blades act as? - ANS Due to their shape, they act
as nozzles
How are the blades in a reaction turbine characterized? - ANS large enterance angle, almost
90 degrees, and a small discharge angle
In a reaction turbine the steam pressure _________ across the stationary blades, and
_________ across the moving blades. - ANS decreases, decreases
2 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
, In a reaction turbine, the velocity _________ in the stationary blades but __________ in the
moving blades. - ANS increases, decreases
What are the disadvantages of a reaction turbine? - ANS 1. the drop in pressure across the
moving blades ecourages steam flow around the end of the blades reducing turbine efficiency
2. the difference in pressure between the inlet and outlet side of each rotor produces an axial
thrust towards the exhaust end of the turbine
In an impluse turbine, what must happen for the steam to transfer all its kentic energy to the
moving blades? - ANS The steam must leave the moving blades at the lowest possible
velocity.
The lowest velocity of the steam leaving the blades of an impulse turbine occurs when the
____________. - ANS The blade velocity is one half the steam velocity.
In an impulse turbine, what is pressure compounding? - ANS Reduces steam and blade
velocty by causing the steam pressure to drop in two or more stages. Two or more impulse
stages are used.
In an impulse turbine, what is velocity compounding? - ANS Consists of one set of sationary
nozzles, a set of moving blades, stationary blades, and moving blades to reduce the velocity.
In an impulse turbine, recuding the steam velocity in two stages results in what? -
ANS roating blades & shaft being 1/2 the speed of a simple, single stage impulse turbine
In an impulse turbine, what is pressure - velocity compounding? - ANS Reduces both steam
pressure and steam velocity in stages.
3 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
