15.1 FUNDAMENTALS👌🏼 Flashcards

1
Q

Explain potential energy and formula

A
  • energy at rest/energy that is stored
  • PE = mgh
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2
Q

Explain kinetic energy and formula

A
  • energy in motion
  • KE = 1/2 x mass x velocity^2
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3
Q

Newton’s first law

A
  • law of inertia
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4
Q

Newton’s second law

A
  • F=ma
  • interplay between force and motion
    E.g thrust proportional to mass of airflow through engine x acceleration of air through engine
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5
Q

Newton’s third law

A
  • law of action and reaction
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6
Q

Explain the Brayton cycle

A

-thermodynamic cycle of gas turbine engine that produces thrust
- has 4 stages (intake, compression, expansion and exhaust)

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7
Q

Explain what occurs at intake (suck)?

A
  • air enters at constant volume.
  • Leaves intake at increased pressure and a decrease in volume.
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8
Q

Explain compressor (squeeze) ?

A
  • air received from intake at slightly increased pressure, with slight decrease in volume
  • air leaves compressor with increased pressure and decrease in volume
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9
Q

Explain expansion (bang)?

A
  • takes place in combustion chamber
  • pressure remain constant, but marked increase in volume
  • expanding gases turn turbine which converts velocity energy to mechanical energy.
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10
Q

Explain exhaust (blow) section?

A
  • convergent duct
  • converts expanding volume and decreasing pressure of gases to a final high velocity
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11
Q

Along the line from 0-2 what change of state occurs

A

Isentropic compression
Pressure increases, volume decreases

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12
Q

Process from 2 to 3 what change of state occurs

A

Isobaric heating

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13
Q

What change of state in lines 3 to 5

A

Isentropic expansion

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14
Q

What occurs from process 0-5

A

Isobaric heat release into nozzle

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15
Q

Formula for force

A

F = ma

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16
Q

What is the formula for work done

A

W = force x distance

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17
Q

Formula for power

A
  • power = Force x distance/time
  • power = work/time
18
Q

What is the unit for power

A

Watt

19
Q

What is 1Nm/s in W

A

1

20
Q

What is the 1Nm in Joules

A

1

21
Q

What is the difference between speed and velocity

A

Speed refers to how fast a object is moving
Velocity refers to speed and direction

22
Q

Explain acceleration

A

-Rate of change of velocity
-change in velocity (m/s) / time (s)
-m/s^2

23
Q

What are the 2 different types of aircraft engines

A
  • Piston type engines
  • Gas turbine engines
24
Q

Which engines performance decrease at higher altitudes

A

Piston engines

25
Q

Are piston engines or gas type engines more fuel efficient

A

Piston engines

26
Q

Which engine can operate at very high altitudes

A
  • gas turbines engines
27
Q

Explain turbojet engines

A
  • high aircraft speeds but very loud
  • has problems with noise and fuel consumption in speed range of 0.8 Mach

Pros: simple design, very high speeds
Cons: high fuel consumption, loud, poor performance at low speeds

28
Q

Explain turbofan engine

A
  • high aircraft speeds possible with good engine efficiency
  • produces around 80% thrust
  • quieter and better fuel consumption
29
Q

Explain a spool arrangement

A
  • consists of a turbine driving a compressor through a shaft
30
Q

Explain twin-spool arrangement?

A
  • high pressure turbine driving the high pressure compressor
  • low pressure turbine driving the low pressure compressor and fan
31
Q

Explain 3 spool arrangement

A
  • high pressure turbine driving high pressure compressor
  • Intermediate pressure turbine driving intermediate compressor
  • low pressure turbine driving the fan
32
Q

Advantages of turbo fan engine

A
  • fuel efficient
  • quieter
  • streamlined appearance
33
Q

Disadvantages of turbofan

A
  • heavy
  • large
34
Q

Explain turboprop engines

A
  • produce shaft horsepower only, which is used to drive propeller
  • extra turbines
  • reduction gearbox to drive propeller
35
Q

Advantages of turboprop engine

A
  • very fuel efficient
  • efficient at mid-range speed and altitude
36
Q

Disadvantages of turboprop engine

A
  • limit forward airspeed
  • gearing systems are heavy and can break down
37
Q

Explain turboshaft engine

A
  • produces shaft power to drive machinery
  • requires small, powerful, lightweight engine
  • e.g. APU supply electric and pneumatic power
38
Q

Advantages of turboshaft engine

A
  • higher power to weight ratio
  • smaller than piston engines
39
Q

Disadvantages of turboshaft engine

A
  • loud
  • gear systems are complex and can break down
40
Q

Explain ‘cold section’

A

Parts of engine from the inlets up through compressors/diffusers

41
Q

Explain ‘hot section’

A
  • refers to ares past the compressors from combustion chamber through exhaust
42
Q

What is the unit of force in the English system measured in

A
  • lbs (pounds)