Chapter 68- Heat Engines And Prime Movers Flashcards
Which has greater thermal efficiency a steam turbine or a steam engine?
Steam turbine
Define a heat engine
The operating cycle uses a working fluid to convert thermal energy to mechanical energy by heating the fluid then allowing it to expand under controlled conditions to produce a useful product
Define working fluid
A mixture of combustion fluid and air, or steam and water, is expanded under controlled conditions in order to preform work
Define a prime mover
A single device which either by itself or as part of an overall heat engine converts a natural source of energy into mechanical motion.
Ex. Steam Turbine
Are electric motors considered prime movers?
No, they are not part of a heat engine nor do they convert a natural source of energy
What is the rankin cycle
The entire boiler system a example of a heat engine
What is the Otto cycle?
Take fuel, mix it with air and burn it to create combustion which forces a piston to create mechanical energy.
Ex- A gas engine
Both a heat engine and a prime mover
What ignites the fuel in a Diesel engine?
The compressed air in the engine cause the fuel to auto ignite.
Name example of fuels used in large scale power production
Solid fuel, coal
Liquid an gaseous hydrocarbons
Water power
Nuclear energy
The main reason a steam plant is so popular
They have the highest overall efficiency
Steam engines are still used when
Slow rotation speed is required
When stroke reversal is required without gearing
Name the different kinds of steam engine
Single cylinder
Vertical engine with a D-valve slide
And a throttling governor
The slide valve of a steam engine is designed to provide for the steam to enter and leave the
Throttling valve
Would a steam turbine be considered a prime mover?
Yes
Large power production plants tend to be of the thermal type because they can burn solid fuels and
The heat cycle they use is most efficient
The cross head of the steam engine
Imparts angular motion to the piston rod
A steam engine piston
Moves fastest at the beginning of its stroke
A routine inspection of an operating steam engine should cover first and foremost
Lubricators
One of the first ways ways to detectable fault in a reciprocating engine is
Sound
The slide valve of a steam engine is designed to
Provide for the steam to enter and leave the cylinder
A steam engine that introduces steam to both sides of the piston is called a
Double acting piston
When the steam is allowed to expand with the inlet valve closed it is called______use of steam
Expansive
To prevent leakage of a steam where the pistons and valve rods pass through the cylinder and the valve box ________is installed
Packing
Which of the following are heat engines:
- ) steam turbine
- ) hydro dam
- ) steam power plant
- ) gas turbine power plant
- ) gasoline engine
3, 4, 5
Which of the following are prime movers:
- ) steam turbine
- ) electric motor
- ) steam engine
- ) gasoline engine
- ) jet engine
1, 3, 4, 5
The advantage of the steam engine is:
- ) never requires lubrication
- ) well suited for rotational motion
- ) well suited for slow speeds
- ) can be reversed with out the use of gears
- )3 & 4
5
In a heat engine where the working fluid is recycled the process is called
A closed cycle
A steam engine will have the steam supply to the cylinder shut off once the piston has travelled
25-35% of the strokes
The reciprocating motion of a steam engine is converted to rotary motion at the
Crankshaft
Whenever feasibly possible, when checking bearings on running pieces of equipment it is wise to
Get accustomed to normal running temperatures and vibrations
