Chapter 68- Heat Engines And Prime Movers

Question 1

Which has greater thermal efficiency a steam turbine or a steam engine?

Answer 1

Steam turbine

Question 2

Define a heat engine

Answer 2

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

Question 3

Define working fluid

Answer 3

A mixture of combustion fluid and air, or steam and water, is expanded under controlled conditions in order to preform work

Question 4

Define a prime mover

Answer 4

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

Question 5

Are electric motors considered prime movers?

Answer 5

No, they are not part of a heat engine nor do they convert a natural source of energy

Question 6

What is the rankin cycle

Answer 6

The entire boiler system a example of a heat engine

Question 7

What is the Otto cycle?

Answer 7

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

Question 8

What ignites the fuel in a Diesel engine?

Answer 8

The compressed air in the engine cause the fuel to auto ignite.

Question 9

Name example of fuels used in large scale power production

Answer 9

Solid fuel, coal
Liquid an gaseous hydrocarbons
Water power
Nuclear energy

Question 10

The main reason a steam plant is so popular

Answer 10

They have the highest overall efficiency

Question 11

Steam engines are still used when

Answer 11

Slow rotation speed is required

When stroke reversal is required without gearing

Question 12

Name the different kinds of steam engine

Answer 12

Single cylinder
Vertical engine with a D-valve slide
And a throttling governor

Question 13

The slide valve of a steam engine is designed to provide for the steam to enter and leave the

Answer 13

Throttling valve

Question 14

Would a steam turbine be considered a prime mover?

Answer 14

Yes

Question 15

Large power production plants tend to be of the thermal type because they can burn solid fuels and

Answer 15

The heat cycle they use is most efficient

Question 16

The cross head of the steam engine

Answer 16

Imparts angular motion to the piston rod

Question 17

A steam engine piston

Answer 17

Moves fastest at the beginning of its stroke

Question 18

A routine inspection of an operating steam engine should cover first and foremost

Answer 18

Lubricators

Question 19

One of the first ways ways to detectable fault in a reciprocating engine is

Answer 19

Sound

Question 20

The slide valve of a steam engine is designed to

Answer 20

Provide for the steam to enter and leave the cylinder

Question 21

A steam engine that introduces steam to both sides of the piston is called a

Answer 21

Double acting piston

Question 22

When the steam is allowed to expand with the inlet valve closed it is called______use of steam

Answer 22

Expansive

Question 23

To prevent leakage of a steam where the pistons and valve rods pass through the cylinder and the valve box ________is installed

Answer 23

Packing

Question 24

Which of the following are heat engines:

1. ) steam turbine
2. ) hydro dam
3. ) steam power plant
4. ) gas turbine power plant
5. ) gasoline engine

Answer 24

3, 4, 5

Question 25

Which of the following are prime movers: 1. ) steam turbine 2. ) electric motor 3. ) steam engine 4. ) gasoline engine 5. ) jet engine

Answer 25

1, 3, 4, 5

Question 26

The advantage of the steam engine is: 1. ) never requires lubrication 2. ) well suited for rotational motion 3. ) well suited for slow speeds 4. ) can be reversed with out the use of gears 5. )3 & 4

Answer 26

5

Question 27

In a heat engine where the working fluid is recycled the process is called

Answer 27

A closed cycle

Question 28

A steam engine will have the steam supply to the cylinder shut off once the piston has travelled

Answer 28

25-35% of the strokes

Question 29

The reciprocating motion of a steam engine is converted to rotary motion at the

Answer 29

Crankshaft

Question 30

Whenever feasibly possible, when checking bearings on running pieces of equipment it is wise to

Answer 30

Get accustomed to normal running temperatures and vibrations