3B2 - Ultimate ABSA Study Guide C1-15 | 995 Questions | With All Correct Answers.

3B2 - Ultimate ABSA Study Guide C1-15 | 995
Questions | With All Correct Answers.
Turbine nozzles convert heat energy into:
a. Potential energy.
b. Enthalpy.
c. Eddy-currents.
d. Kinetic energy.
e. Pressure.
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.
D


Flange warming on a steam turbine decreases:
a. Creep.
b. Start up time.
c. Movement.
d. Radiation losses.
e. Noises.
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.
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.
d. 1,5,4.
e. 1,5,6.
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.
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.
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

a. 1,2,4
b. 1,3,4
c. 2,3,4
d. 1,2,3
e. 1,2,3,4
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.
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.
A


Extraction turbines are turbines where steam is extracted at one or more points at constant:
a. Flow.
b. Pressure.
c. Load.
d. Temperature.
e. Efficiency.
B


_____ turbines are large turbines with parallel shafts with a generator on each shaft.
a. Condensing.
b. Tandem-compound.
c. Extraction-bleeder.
d. Condensing-bleeder.
e. Cross-compound.
E


Steam turbine stationary nozzles create a:
1. Decrease in steam pressure.
2. Increase in steam enthalpy.
3. Increase in steam coefficient of friction.
4. Increase in steam velocity.
a. 1,2,3
b. 1,3,4
c. 1,4
d. 2,3
e. 3, 4.
C


Steam turbine casing joints are made steam tight by matching _____ exactly.
a. Thin high temperature gaskets.
b. Bowel pins.
c. Alignment notches.
d. Flange faces.
e. Rubber gaskets.
D


The purpose of the bucket or moving blade on the rotor is to convert the _____ energy of the steam
into _____ energy.
a. Heat, potential.
b. Kinetic, useful.
c. Kinetic, mechanical.
d. Heat, kinetic.
e. Mechanical, kinetic.
C

, Reaction steam turbines often use _____ seals as part of the shroud with the seal clearances kept as
small as possible.
a. Radial.
b. Water.
c. Radial and axial.
d. Carbon.
e. Axial.
C


Reaction turbine blades (moving):
1. Convert the kinetic energy of the steam into mechanical
energy.
2. Convert heat energy into kinetic energy.
3. Are nozzle shaped.
4. Increase the absolute velocity.
a. 1, 2, 3
b. 2, 3, 4
c. 1, 3, 4
d. 1, 2
e. 1, 3.
A


During start up of a steam turbine the thrust block is pushed against a stop in the direction of the
exhaust for:
a. Maximum seal clearance.
b. Minimum seal clearance.
c. Maximum blade efficiency.
d. Maximum blade clearance.
e. Minimum blade clearance.
D


It is general practice to let the thickness of the walls and flanges _____ from inlet to exhaust end of a
steam turbine casing:
a. Decrease.
b. Fluctuate.
c. Be the same.
d. Vary.
e. Increase.
A


A condensing-bleeder turbine can bleed up to _____ of the total steam flow.
a. 1%
b. 15%
c. 2%
d. 10%
e. 5%.
C


A steam turbine water seal is used _____ to insure that no air leaks
in along the shaft:
a. On start-up
b. At speed below 2000 rev/mm