Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Module 15 - Engines > M15.01 Fundamentals > Flashcards

M15.01 Fundamentals Flashcards

1
Q

What is the formula for force?

A

Mass time acceleration
In newtons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the formula for weight?

A

Mass time acceleration due to gravity
In newtons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is work?

A

Work is done when an object is moved over a distance. It is force multiplied by distance
Force = force times distance
In Nm or joules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is power?

A

Power is the rate of work
Power = work divided by time
In Watt

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the two forms of mechanical energy

A

Potential
Kinetic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the formula for potential energy?

A

PE=mgh

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the formula for kinetic energy?

A

KE = 1/2mV squared

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is Newtons first law?

A

Newton’s first law of motion is called the law of inertia. It states:
A body at rest remains at rest and a body in motion continues to move at a constant velocity unless acted upon by an unbalanced external force

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is newtons second law?

A

Newton’s Second Law
Newton’s second law of motion is the interplay between force and motion and allows us to analyse the motion of any object. Newton’s second law states:
That the acceleration produced in a mass by a force acting on it is directly proportional to the force and inversely proportional to the mass

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is Newtons third law?

A

Every action has an equal and opposite reaction. This means that no matter what the circumstances, when one object exerts a force on a second object, the second must exert an equal and oppositely directed force on the first

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How does a gas turbine increase the velocity of the air?

A

To obtain the increased air velocity …
The pressure energy is increased
Addition of heat energy
Final conversion back to kinetic energy in the form of a high velocity jet efflux

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What combustion process does a gas turbine work under?

A

Heating at constant pressure (Isobaric)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the name of a constant pressure process?

A

Isobaric

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Wha t is the name of a constant temperature process?

A

Isothermal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the name of a constant velocity process?

A

Isochoric

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

hat are the disadvantages of a piston engine?

A

The performance of piston engines decreases at higher altitudes and they can be too large for the aircraft because the ratio of weight and power decreases with the size of the piston engines. Therefore, piston type engines are only used on very small aircraft

17
Q

What principles do jet engines work under?

A

Reaction

18
Q

How can air pressure be increased in a gas turbine?

A

Mechanically by use of a compressor or thermally by increasing the volume of air when a fuel / air mixture is burned or heated.
Engines use both of these mesures

19
Q

What determines thrust in a gas turbine?

A

Mass of the ambient air which is accelerated, the other is the quantity of the acceleration itself

20
Q

How is the airs acceleration determined?

A

By knowing the difference between the outlet velocity of the air at the jet nozzle compared to the inlet velocity

21
Q

What are the four factors that create changes to an engines thrust?

A

The ambient air pressure
The air temperature
The operation altitude
The airspeed of the aircraft

22
Q

What happens with high altitudes with relation to thrust production?

A

The colder air temperatures at higher altitudes give a small increase in thrust, but the decrease in thrust is greater because the decrease of air density is much bigger

23
Q

Explain the effects of airspeed on thrust

A

As air speed increases, thrust decreases, this is because the difference between the efflux and the intake velocity decreases.
However This is somewhat negated by the fact that as airspeed increases so does the ram effect. the increased ram effect increases the thrust.
Therefore these effects are in fact a combination of the two.

24
Q

On a turbo fan engine how do the fan propel the air?

A

High airflow to a relatively low outlet velocity

25
Q

On a turbo fan engine how does the core propel the air?

A

Accelerates a small amount of airflow to a high outlet velocity

26
Q

What are the typical bypass ratios of high bypass engines?

A

between 4:1 to 9:1

27
Q

What are the typical bypass ratios of high bypass engines?

A

between 4:1 to 9:1

28
Q

What are the two types of engine manufacturing methods?

A

Modular and non modular

29
Q

What are the benefits of using modular construction?

A

These engine modules are pre-assembled and balanced. They are specially designed to be removed and replaced more easily

30
Q

What are the typical major engine modules?

A

Fan module
Core module
Gearbox
Low pressure turbine module

31
Q

What is the main design aim for engine materials?

A

The main design aim for engine materials is that they must be strong enough for their individual tasks. They must also be as light and cheap as possible

32
Q

What material is used for the fan outlet guide vanes, spiner, and flow path liner?

A

Composites

33
Q

What material is used for the MGB fan exit case and fan case?

A

Aluminium

34
Q

Where are ceramic coatings used?

A

In the combustor and the high pressure turbine

35
Q

Where are steel alloys used?

A

For the N1 drive shaft, engine bearings, main structural frames

36
Q

Where are cobalt base alloys used?

A

Cobalt base alloys are very heat resistant and as such are used on the stator of the first stage of the high pressure turbine.

37
Q

Where is titanium used?

A

Titanium alloys are as stong as steel but half the weight, they can withstand high centrifugal loads. are used in the fan, the LP compressor and the front stages of the HP compressor

38
Q

Where is nickel used?

A

In the HP compressor, the combustion section, and the HP and LP turbines.

Module 15 - Engines (22 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions