Unit 7 Types of prime movers and Heat engines Flashcards
Using a compressed air starting motor is a common method of starting: Select one: a. Large stationary diesel engines b. Small two-stroke engines c. Gasoline engines d. Aircraft engines
a. Large stationary diesel engines
A steam engine piston:
Select one:
a. Moves fastest at the end of its stroke
b. Produces the most force at the end of its stroke
c. Is lubricated inside the crankcase by the splash method
d. Moves fastest from the start to the mid point of its stroke
d. Moves fastest from the start to the mid point of its stroke
When \_\_\_\_\_\_\_\_\_\_\_\_\_ leached away from cooling tower wood, it is less able to resist decay. Select one: a. sap is b. lignin is c. cellulose is d. natural extractives are
d. natural extractives are
During a single rotation of a 4-stroke cycle gasoline engine crankshaft, the engine undergoes
Select one:
a. a compression stroke, immediately followed by an exhaust stroke
b. an intake stroke, immediately followed by a power stroke
c. an intake stroke, immediately followed by an exhaust stroke
d. a power stroke, immediately followed by an exhaust stroke
d. a power stroke, immediately followed by an exhaust stroke
The slide valve of a steam engine is designed to:
Select one:
a. Drain the condensate from the cylinder during warm-up
b. Provide lubrication for the steam engine
c. Allow steam to enter and leave the cylinder
d. Prevent the engine from over-speeding
c. Allow steam to enter and leave the cylinder
An arrangement of a steam system and a gas turbine, working as a single installation, is called a Select one: a. a combined cycle plant b. a cogeneration system c. a once-through system d. a two-stage system
a. a combined cycle plant
One complete movement of the piston in one direction requires \_\_\_\_\_\_\_\_\_\_\_\_ of the engine crankshaft: Select one: a. One-half revolution b. One revolution c. Two revolutions d. Four revolutions
a. One-half revolution
An engine that has one power stroke every second rotation of the crankshaft is a: Select one: a. two-stroke diesel engine b. four-stroke natural gas engine c. two-stroke gasoline engine d. double-acting engine
b. four-stroke natural gas engine
Excessive wind velocity in a natural draft cooling tower may cause: Select one: a. Damaged louvres b. High drift losses c. Unstable sump water level d. Over-cooling of the water
b. High drift losses
A gas turbine is most efficient when:
Select one:
a. both turbine shafts run at the same speed
b. the combustion chamber is kept cool
c. the ambient air temperature is low
d. operated at the highest combustion temperature that the construction materials permit.
d. operated at the highest combustion temperature that the construction materials permit.
The injection pump of a diesel engine is driven by: Select one: a. Piston action b. The governor c. The gudgeon pin d. A camshaft
d. A camshaft
The output power of a gas turbine depends upon
Select one:
a. the mass of hot gas passing through the turbine per unit time
b. the temperature at the turbine inlet in Kelvin
c. the drive gear ratio between the turbine and compressor
d. the difference between inlet air and turbine exhaust temperature
a. the mass of hot gas passing through the turbine per unit time
Compression ignition engines:
Select one:
a. Mix oil into the fuel for lubrication
b. Will compress air only on the compression stroke
c. Will compress air only on the power stroke
d. Require a spark timing device
b. Will compress air only on the compression stroke
Cylinder scavenging:
Select one:
a. Refers to the flow of fuel air mixture into a diesel engine.
b. Refers to the removal of exhaust gases from the cylinder
c. May be aided with air injectors to rapidly fill the cylinder
d. Is performed by a special piston ring that removes excessive oil from the cylinder walls
b. Refers to the removal of exhaust gases from the cylinder
The turbine overspeed trip:
Select one:
a. Prevents the turbine from exceeding the maximum rated speed
b. Adjusts steam flow to keep the speed at set point
c. Opens the sentinel valve
d. Alerts the operator of excessive turbine RPM
a. Prevents the turbine from exceeding the maximum rated speed
Despite their size and complexity, steam plants are widely used because:
Select one:
a. they are relatively inexpensive to build
b. they do not require trained operators
c. they require little maintenance or repairs
d. they can use a wide variety of heat sources, including hydrocarbon fuels, waste heat, solar energy and nuclear energy.
d. they can use a wide variety of heat sources, including hydrocarbon fuels, waste heat, solar energy and nuclear energy.
A “prime mover” is
Select one:
a. the same as a “heat engine”
b. a device that uses a primary energy source to produce mechanical work
c. a device used to remove air from pumping systems
d. a device that stores mechanical energy, such as a flywheel.
b. a device that uses a primary energy source to produce mechanical work
_______________ causes the fuel to ignite in a diesel engine.
Select one:
a. A precisely timed glow plug.
b. The pressure of the injected fuel.
c. The high temperature compressed air in the engine cylinder.
d. The fuel injector nozzle.
c. The high temperature compressed air in the engine cylinder.
Clean air flows into a gas turbine regenerator from: Select one: a. the inlet air pre-filter b. the combustor c. the gasifier d. the compressor outlet
d. the compressor outlet
In theory, impulse turbines:
Select one:
a. Have a velocity drop through the nozzle
b. Have no pressure drop through the moving blades
c. Can only use only low-pressure steam
d. Develop the most torque of all turbines
b. Have no pressure drop through the moving blades
The turbine overspeed trip:
Select one:
a. Prevents the turbine from exceeding the maximum rated speed
b. Adjusts steam flow to keep the speed at set point
c. Opens the sentinel valve
d. Alerts the operator of excessive turbine RPM
a. Prevents the turbine from exceeding the maximum rated speed
A starting device for a gas turbine
Select one:
a. must be an electric motor
b. is necessary for all gas turbines
c. keeps rotating the turbine shaft until the turbine is up to full load
d. is also called “barring gear”
b. is necessary for all gas turbines
A counter-flow cooling tower \_\_\_\_\_\_\_\_\_\_\_\_\_ than a crossflow cooling tower. Select one: a. is shorter b. requires less floor space c. requires less fan power d. has a lower pressure drop
b. requires less floor space
The reciprocating motion of a steam engine is converted to rotary motion: Select one: a. At the end of the piston stroke b. By the camshaft c. At the crankshaft d. By the valve gear
c. At the crankshaft
A gas turbine compressor:
Select one:
a. must be a multi-stage compressor
b. is always an axial compressor
c. can be driven by the load turbine
d. must be intercooled
c. can be driven by the load turbine
The output power of a gas turbine depends upon
Select one:
a. the mass of hot gas passing through the turbine per unit time
b. the temperature at the turbine inlet in Kelvin
c. the drive gear ratio between the turbine and compressor
d. the difference between inlet air and turbine exhaust temperature
a. the mass of hot gas passing through the turbine per unit time
The injection pump of a diesel engine is driven by: Select one: a. Piston action b. The governor c. The gudgeon pin d. A camshaft
d. A camshaft
Which of the following is a prime mover ? Select one: a. An electric generator b. A gas turbine c. An air compressor d. A boiler
b. A gas turbine
Which of the following comes earliest in the start-up sequence of a steam turbine?
Select one:
a. Open the steam inlet valve slightly to start the turbine rolling.
b. Manually test the overspeed trip.
c. Reset the overspeed trip.
d. Close the casing drain valve and ensure the casing drain steam trap remains in service
c. Reset the overspeed trip.
Despite their size and complexity, steam plants are widely used because:
Select one:
a. they are relatively inexpensive to build
b. they do not require trained operators
c. they require little maintenance or repairs
d. they can use a wide variety of heat sources, including hydrocarbon fuels, waste heat, solar energy and nuclear energy.
d. they can use a wide variety of heat sources, including hydrocarbon fuels, waste heat, solar energy and nuclear energy.
One complete movement of the piston in one direction requires \_\_\_\_\_\_\_\_\_\_\_\_ of the engine crankshaft: Select one: a. One-half revolution b. One revolution c. Two revolutions d. Four revolutions
a. One-half revolution
An essential auxiliary in a gas turbine installation is: Select one: a. an air heater b. a generator c. a water injection system d. a starting motor
d. a starting motor
A major difficulty encountered with a two-stroke cycle engine is:
Select one:
a. The lack of torque at high speed
b. The difficulty in cold weather starting
c. The high speeds compared to an equivalent four-stroke engine
d. Exhausting the spent gases from the cylinder
d. Exhausting the spent gases from the cylinder
A gas turbine:
Select one:
a. Expands hot gases through the compressor
b. Output increases when using air of maximum density
c. Operates the best when the inlet air is hot
d. Output increases when equipped with an air preheater
b. Output increases when using air of maximum density
The fuel for a diesel engine is:
Select one:
a. admitted to the cylinder during the intake stroke
b. mechanically atomized by high pressure
c. fed to the carburetor under pressure
d. mixed with air in the intake manifold
b. mechanically atomized by high pressure
The purpose of a spark plug is to: Select one: a. Ignite the fuel air mixture in a gasoline engine b. Warm the cylinder of a diesel engine c. Lower the ignition point of the fuel d. Ignite the air in the cylinder
a. Ignite the fuel air mixture in a gasoline engine
Turbine lubricating oil: Select one: a. Contaminates the exhaust steam b. Must mix well with water c. Can be used to operate the turbine governor d. Lubricates the labyrinth gland
c. Can be used to operate the turbine governor
The purpose of turbine glands is to prevent:
Select one:
a. cool and lubricate the shaft
b. Steam escaping from the turbine
c. Steam from entering the lubrication system
d. shaft movement due to axial thrust
b. Steam escaping from the turbine
Between a valve and a pushrod, there is a
Select one:
a. rocker arm
b. connecting rod
c. wrist pin
d. camshaft
a. rocker arm
A “heat engine” is an operating cycle that uses a working fluid to convert:
Select one:
a. Thermal energy to chemical energy
b. Thermal energy to potential energy
c. Mechanical energy to electrical energy
d. Thermal energy to mechanical energy
d. Thermal energy to mechanical energy