3B2 Ch 1 Flashcards
The entrance angle of a reaction blade is:
Select one:
a.
Parallel to the rotational direction
b.
Low, so as to reduce frictional losses
c.
Almost 90 degrees
d.
The same as the exit angle
e.
Set at 45 degrees to the nozzle angle
c.
Almost 90 degrees
A topping turbine is a special application of a _____ turbine.
Select one:
a.
Condensing
b.
Extraction
c.
Condensing-bleeder
d.
Tandem-compound
e.
Back-pressure
e.
Back-pressure
A thrust adjusting gear __________.
Select one:
a.
Is found on impulse turbines
b.
Adjust the thrust generated by the turbine
c.
Positions the turbine rotor axially
d.
Compensates for steam pressure variations
e.
Is adjusted to provide minimum clearances on start-up
c.
Positions the turbine rotor axially
When the exit pressure of a steam turbine nozzle is less than _____ times the inlet pressure, then a _____ nozzle will be used.
Select one:
a.
0.757, convergent
b.
0.577, convergent-divergent
c.
0.757, convergent-divergent
d.
0.757, convergent
e.
0.577, convergent or convergent-divergent
b.
0.577, convergent-divergent
In a condensing-bleeder turbine, up to 2% of the total steam flow may be bled off. What is the bleed-steam used for?
Select one:
a.
Building heating
b.
Relieving pressure
c.
Atomization of the fuel
d.
To be reheated in the boiler
e.
Feedwater heating
e.
Feedwater heating
Proper expansion of steam through a turbine nozzle depends on which of the following?
1. Operation at the design pressure
2. Operation at the design rotational speed
3. Operation at the design temperature
4. Selection of the proper nozzle material
Select one:
a.
1, 2
b.
2, 3
c.
3, 4
d.
1, 3
e.
2, 4
d.
1, 3
When disc rotors are assembled, the discs are heated until they slide easily along the shaft so they can be positioned in the correct location on the shaft and shaft key. What does the small clearance between the discs prevent?
Select one:
a.
Noise
b.
Slippage
c.
Thermal stress in the shaft
d.
Acceleration
e.
Vibration
c.
Thermal stress in the shaft
Labyrinth seals are which of the following?
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
Select one:
a.
1, 2
b.
2, 4, 5
c.
3, 4, 5
d.
4, 5
e.
1, 2, 3
d.
4, 5
The purpose of the bucket or moving blade on the rotor of an impulse turbine is to convert the _____ energy of the steam into _____ energy.
Select one:
a.
Heat, potential
b.
Kinetic, useful
c.
Kinetic, mechanical
d.
Heat, kinetic
e.
Mechanical, kinetic
c.
Kinetic, mechanical
In pressure-compound steam turbines, which of the following are true?
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.
Select one:
a.
1, 2, 3
b.
2, 3, 4
c.
1, 3, 4
d.
2, 4
e.
2, 3, 4
d.
2, 4
What is the purpose of compounding in a steam turbine?
Select one:
a.
Create pressure-velocity compounding
b.
Reduce steam and blade velocity
c.
Create higher rotational speeds
d.
Allow the use of higher steam pressures
e.
Allow the use of smaller turbines
b.
Reduce steam and blade velocity
On larger turbines, which component is split in a horizontal direction?
Select one:
a.
Shaft
b.
Governor
c.
Cylinder
d.
Rotor
e.
Drum
c.
Cylinder
In a reaction turbine, which of the following are true?
1. Velocity increases in the moving blades
2. Velocity decreases in the stationary blades
3. Pressure drops in the moving blades
4. Pressure drops in the stationary blades
Select one:
a.
1, 2
b.
3, 4
c.
1, 2, 3
d.
2, 3, 4
e.
1, 2, 3, 4
b.
3, 4
