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100問 • 1年前
  • Guevara Official
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    問題一覧

  • 1

    Newton’s 2nd law used

    to calculate the amount of thrust produced by the engine

  • 2

    Thrust can be increased by increasing

    increasing air mass flown to engine or gases acceleration through the engine

  • 3

    Thrust in a gas turbine engine is produced by

    Compressor (increase air pressure) and Combustor (increase gases acceleration

  • 4

    The output of the engine when the aircraft in flight is called

    net thrust

  • 5

    ESHP

    = SHP + Jet Thrust Addition of SHP to jet thrust. 1hp=745.7

  • 6

    Propulsive efficiency

    is the ability of engine to drive the aircraft in flight

  • 7

    The specific fuel consumption

    thrust produced per pound of fuel consumed

  • 8

    At 400 knots Ram effect

    increase

  • 9

    .... thrust increase with small increase in RPM

    At higher engine speeds

  • 10

    As altitude increase air pressure (density) & temperature

    decrease

  • 11

    Aircraft altitude & ambient temperature

    affect the inlet air density.

  • 12

    Gas turbine engine efficiency increases at altitude

    due to drag decrease

  • 13

    As temperature increase air density decrease

    which negatively effect engine thrust and vice versa

  • 14

    Lower temperature gives

    greater mass flow and greater thrust

  • 15

    the working cycle of the heat engine

    as constant-pressure cycle

  • 16

    gas inside the combustion section of gas turbine engine

    reduce from front to rear

  • 17

    Pressure in combustion chamber

    virtually constant.

  • 18

    The rocket is

    a non-air breathing engine means it does not use atmospheric air to support combustion

  • 19

    Pulse Jet

    it has additional spring loaded valves in the air intake

  • 20

    The turbofan mixture of a

    turbojet and a turboprop, literally handles a hot air mass and a cold air mass

  • 21

    ......... always maintain high pressure compressor speed constant.

    Governor

  • 22

    A high bypass engine is more efficient because it is similar to the

    to the propeller by accelerating large mass of air at a low rate of acceleration

  • 23

    Easier starting (the small.... needs to be rotated by the starter

    HP compressor only

  • 24

    ..... is gas coupling with compressor.... mechanically connected.

    Free turbine&not

  • 25

    ......... drives the output shaft which drives propeller in turbo-prop engine and rotor in turbo-shaft engines

    Free turbine

  • 26

    By pass ratio 5:1

    indicates that bypass flow is five times the hot stream

  • 27

    1st digit represent the

    bypass air

  • 28

    2nd digit represent to

    engine core air

  • 29

    The highest air pressure

    at compressor outlet

  • 30

    In turbojet engine the function of the air intake section is to

    deliver a smooth and uniform stream of air to the compressor inlet

  • 31

    Pitot intake is

    divergent duct (front to rear) and best suited for subsonic aircrafts

  • 32

    Pitot intake typical efficiency is

    96-99%

  • 33

    Convergent-Divergent intake,

    fixed duct design convergent then divergent duct. Used to slow down air flow speed to subsonic before compressor

  • 34

    In an aircraft flying at supersonic speed to reduce the air velocity at compressor the variable intake

    throat area decreased

  • 35

    Anti Icing System Function

    used to prevent ice formation of engine intake

  • 36

    Intake & inlet guide vanes are anti iced using

    bled hot air from the compressor

  • 37

    Icing condition when OAT is

    (10°+ C) with visible moisture.

  • 38

    Turboprop intake and propeller use electrical heater mats

    operated part continuous & part intermittent

  • 39

    The advantage of electrical anti-icing system used on engine inlets is

    to minimal loss of engine power or thrust

  • 40

    The centrifugal compressor is ideally suited

    to reverse flow turboprop engines

  • 41

    double entry compressor problem is

    difficulty in designing.

  • 42

    Compressor stage

    is a raw of rotor and a raw of stator

  • 43

    Stator

    increase pressure and control the direction of airflow.

  • 44

    Rotor

    increase air velocity

  • 45

    Compressor blades and diameter getting smaller (front to rear) to maintain........ through the compressor.

    axial velocity

  • 46

    ......... is the ratio between compressor outlet pressure to compressor inlet pressure

    Compressor pressure ratio

  • 47

    The primary factor

    that control the pressure ratio is number of stages in the compressor

  • 48

    The highest gas pressure through gas turbine engine

    at compressor outlet

  • 49

    Root

    is lowest stagger angle at the root

  • 50

    Compressor RPM is

    limited by blade tip speed

  • 51

    To calculate compressor outlet pressure you need to

    multiply inlet pressure with compression ratio

  • 52

    A combination type (Hybrid compressor) used in

    small gas turbine engines with reverse flow combustion

  • 53

    Engine design point is the point which engine will operate during most of its service,

    it is based on cruise speed and altitude (air density)

  • 54

    Twin spool compressor is more

    flexibility of operation and greater resistance to surge

  • 55

    Low pressure compressor runs at

    lower RPM than high pressure compressor

  • 56

    Single spool compressor is

    less efficient

  • 57

    Variable stator vanes and bleed valve used to

    avoid surge.

  • 58

    In a centrifugal flow compressor the high efficiency of compressor achieved by

    keeping clearance between the impeller and casing As small as possible to preventing excessive air leakage

  • 59

    The function of snubber mid span shroud used on fan blade

    to support fan blade and prevent aerodynamic instability

  • 60

    centrifugal compressor Advantage .

    Simple ,Low weight & cost and High pressure rise per stage

  • 61

    Centerifugal compressor Disadvantage

    Large frontal area and limited number of stages.

  • 62

    Diffuser It is a divergent shape located between compressor and combustion chamber

    used to decrease the velocity of the air.

  • 63

    Compressed air is mixed with fuel, in the

    combustion chamber.

  • 64

    Over rich mixture will produce

    exhaust smoke and carbon particles formed inside combustion chamber.

  • 65

    The method used a network of passages between two laminated skins forming the flame tube is

    a transpiration cooling

  • 66

    The purpose of dilution zone in the combustion chamber is

    to protect combustion chamber from melting.

  • 67

    The overall fuel/air ratio entering combustion chamber is approximately

    (45:1 – 130:1)

  • 68

    Reverse Flow Combustion is best suited for

    turbo-prop and turbo-shaft engines.

  • 69

    Combustion in Multiple-can Combustion Chamber occurs in

    two cans by igniter plugs then moved through interconnector tubes to the remaining cans

  • 70

    Compressor outlet and the duct at the forward part of the combustion is

    snout shape.

  • 71

    Another name for can – annular combustion chamber is.

    A tubo-annular.

  • 72

    Can-annular compared to a multiple can design is

    smaller and lighter

  • 73

    Rich mixture that has

    too much fuel for the primary air in the combustion chamber

  • 74

    The best ratio of air fuel mixture within

    the primary dilution zone is 15:1

  • 75

    The primary condition that are necessary for safe and correct combustion

    is correct mixture ratio and air velocity must be slow enough

  • 76

    can annular combustion chamber

    has a set of flame tubes with common outer casing and

  • 77

    Annular combustion chamber

    disadvantages Removal difficult and time consuming

  • 78

    Annular combustion chamber

    advantages; Better thermal load distribution for the turbine

  • 79

    Swirl vanes cause

    air flow vortex and help air fuel mixing

  • 80

    Combustion stability means

    smooth burning coupled with ability to remain alight over a large range of air fuel ratio and air mass flow

  • 81

    Turbine section converting gas stream kinetic energy

    into mechanical energy to drive compressor

  • 82

    Turbine Blades Material

    Nickel alloy.

  • 83

    Impulse type Turbine Blades used in

    (Starter blades)

  • 84

    Impulse-reaction type used in

    (all modern jet engines).

  • 85

    Turbine blade secured to the disc using

    fir tree root with locking plate

  • 86

    Cooling air enters the fir-tree turbine blades though the

    base of the root.

  • 87

    Fir-Tree turbine blades attachment .

    allows slight movement

  • 88

    The space between two nozzle guide vanes forms

    a convergent duct in order to increase velocity.

  • 89

    the cooling air flows through the hollow nozzle vanes and rotor blades

    this method is known as Convection cooling

  • 90

    Blade Twist

    To ensure equal work done all over the blade length (root to tip)

  • 91

    Nozzle Guide Vanes Function

    direct gases in proper angle to first stage turbine nozzle

  • 92

    Nozzle Guide Vanes

    Cooling by ceramic coating and bleed air.

  • 93

    Creep is permanent elongation in rotor blades, resulting of

    thermal stress and high centrifugal force .

  • 94

    Most creep resistant blades are

    single structure blades

  • 95

    ACC cools turbine casing to

    reduce tip losses and improve efficiency in the cruise

  • 96

    Shrouded turbine rotor blades used

    to reduce vibration and improve air flow.

  • 97

    The efficiency of a turbine blade increases proportional, as its

    rotational speed increases

  • 98

    The nozzle guide vanes and at the rotor blades are cooled by the method of

    film cooling .

  • 99

    Running clearance on a turbine disk is kept to a minimum to reduce

    tip losses

  • 100

    advantage of an axial turbine is that it

    allows very high airflow which is needed to create the high thrust of modern engines

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    問題一覧

  • 1

    Newton’s 2nd law used

    to calculate the amount of thrust produced by the engine

  • 2

    Thrust can be increased by increasing

    increasing air mass flown to engine or gases acceleration through the engine

  • 3

    Thrust in a gas turbine engine is produced by

    Compressor (increase air pressure) and Combustor (increase gases acceleration

  • 4

    The output of the engine when the aircraft in flight is called

    net thrust

  • 5

    ESHP

    = SHP + Jet Thrust Addition of SHP to jet thrust. 1hp=745.7

  • 6

    Propulsive efficiency

    is the ability of engine to drive the aircraft in flight

  • 7

    The specific fuel consumption

    thrust produced per pound of fuel consumed

  • 8

    At 400 knots Ram effect

    increase

  • 9

    .... thrust increase with small increase in RPM

    At higher engine speeds

  • 10

    As altitude increase air pressure (density) & temperature

    decrease

  • 11

    Aircraft altitude & ambient temperature

    affect the inlet air density.

  • 12

    Gas turbine engine efficiency increases at altitude

    due to drag decrease

  • 13

    As temperature increase air density decrease

    which negatively effect engine thrust and vice versa

  • 14

    Lower temperature gives

    greater mass flow and greater thrust

  • 15

    the working cycle of the heat engine

    as constant-pressure cycle

  • 16

    gas inside the combustion section of gas turbine engine

    reduce from front to rear

  • 17

    Pressure in combustion chamber

    virtually constant.

  • 18

    The rocket is

    a non-air breathing engine means it does not use atmospheric air to support combustion

  • 19

    Pulse Jet

    it has additional spring loaded valves in the air intake

  • 20

    The turbofan mixture of a

    turbojet and a turboprop, literally handles a hot air mass and a cold air mass

  • 21

    ......... always maintain high pressure compressor speed constant.

    Governor

  • 22

    A high bypass engine is more efficient because it is similar to the

    to the propeller by accelerating large mass of air at a low rate of acceleration

  • 23

    Easier starting (the small.... needs to be rotated by the starter

    HP compressor only

  • 24

    ..... is gas coupling with compressor.... mechanically connected.

    Free turbine&not

  • 25

    ......... drives the output shaft which drives propeller in turbo-prop engine and rotor in turbo-shaft engines

    Free turbine

  • 26

    By pass ratio 5:1

    indicates that bypass flow is five times the hot stream

  • 27

    1st digit represent the

    bypass air

  • 28

    2nd digit represent to

    engine core air

  • 29

    The highest air pressure

    at compressor outlet

  • 30

    In turbojet engine the function of the air intake section is to

    deliver a smooth and uniform stream of air to the compressor inlet

  • 31

    Pitot intake is

    divergent duct (front to rear) and best suited for subsonic aircrafts

  • 32

    Pitot intake typical efficiency is

    96-99%

  • 33

    Convergent-Divergent intake,

    fixed duct design convergent then divergent duct. Used to slow down air flow speed to subsonic before compressor

  • 34

    In an aircraft flying at supersonic speed to reduce the air velocity at compressor the variable intake

    throat area decreased

  • 35

    Anti Icing System Function

    used to prevent ice formation of engine intake

  • 36

    Intake & inlet guide vanes are anti iced using

    bled hot air from the compressor

  • 37

    Icing condition when OAT is

    (10°+ C) with visible moisture.

  • 38

    Turboprop intake and propeller use electrical heater mats

    operated part continuous & part intermittent

  • 39

    The advantage of electrical anti-icing system used on engine inlets is

    to minimal loss of engine power or thrust

  • 40

    The centrifugal compressor is ideally suited

    to reverse flow turboprop engines

  • 41

    double entry compressor problem is

    difficulty in designing.

  • 42

    Compressor stage

    is a raw of rotor and a raw of stator

  • 43

    Stator

    increase pressure and control the direction of airflow.

  • 44

    Rotor

    increase air velocity

  • 45

    Compressor blades and diameter getting smaller (front to rear) to maintain........ through the compressor.

    axial velocity

  • 46

    ......... is the ratio between compressor outlet pressure to compressor inlet pressure

    Compressor pressure ratio

  • 47

    The primary factor

    that control the pressure ratio is number of stages in the compressor

  • 48

    The highest gas pressure through gas turbine engine

    at compressor outlet

  • 49

    Root

    is lowest stagger angle at the root

  • 50

    Compressor RPM is

    limited by blade tip speed

  • 51

    To calculate compressor outlet pressure you need to

    multiply inlet pressure with compression ratio

  • 52

    A combination type (Hybrid compressor) used in

    small gas turbine engines with reverse flow combustion

  • 53

    Engine design point is the point which engine will operate during most of its service,

    it is based on cruise speed and altitude (air density)

  • 54

    Twin spool compressor is more

    flexibility of operation and greater resistance to surge

  • 55

    Low pressure compressor runs at

    lower RPM than high pressure compressor

  • 56

    Single spool compressor is

    less efficient

  • 57

    Variable stator vanes and bleed valve used to

    avoid surge.

  • 58

    In a centrifugal flow compressor the high efficiency of compressor achieved by

    keeping clearance between the impeller and casing As small as possible to preventing excessive air leakage

  • 59

    The function of snubber mid span shroud used on fan blade

    to support fan blade and prevent aerodynamic instability

  • 60

    centrifugal compressor Advantage .

    Simple ,Low weight & cost and High pressure rise per stage

  • 61

    Centerifugal compressor Disadvantage

    Large frontal area and limited number of stages.

  • 62

    Diffuser It is a divergent shape located between compressor and combustion chamber

    used to decrease the velocity of the air.

  • 63

    Compressed air is mixed with fuel, in the

    combustion chamber.

  • 64

    Over rich mixture will produce

    exhaust smoke and carbon particles formed inside combustion chamber.

  • 65

    The method used a network of passages between two laminated skins forming the flame tube is

    a transpiration cooling

  • 66

    The purpose of dilution zone in the combustion chamber is

    to protect combustion chamber from melting.

  • 67

    The overall fuel/air ratio entering combustion chamber is approximately

    (45:1 – 130:1)

  • 68

    Reverse Flow Combustion is best suited for

    turbo-prop and turbo-shaft engines.

  • 69

    Combustion in Multiple-can Combustion Chamber occurs in

    two cans by igniter plugs then moved through interconnector tubes to the remaining cans

  • 70

    Compressor outlet and the duct at the forward part of the combustion is

    snout shape.

  • 71

    Another name for can – annular combustion chamber is.

    A tubo-annular.

  • 72

    Can-annular compared to a multiple can design is

    smaller and lighter

  • 73

    Rich mixture that has

    too much fuel for the primary air in the combustion chamber

  • 74

    The best ratio of air fuel mixture within

    the primary dilution zone is 15:1

  • 75

    The primary condition that are necessary for safe and correct combustion

    is correct mixture ratio and air velocity must be slow enough

  • 76

    can annular combustion chamber

    has a set of flame tubes with common outer casing and

  • 77

    Annular combustion chamber

    disadvantages Removal difficult and time consuming

  • 78

    Annular combustion chamber

    advantages; Better thermal load distribution for the turbine

  • 79

    Swirl vanes cause

    air flow vortex and help air fuel mixing

  • 80

    Combustion stability means

    smooth burning coupled with ability to remain alight over a large range of air fuel ratio and air mass flow

  • 81

    Turbine section converting gas stream kinetic energy

    into mechanical energy to drive compressor

  • 82

    Turbine Blades Material

    Nickel alloy.

  • 83

    Impulse type Turbine Blades used in

    (Starter blades)

  • 84

    Impulse-reaction type used in

    (all modern jet engines).

  • 85

    Turbine blade secured to the disc using

    fir tree root with locking plate

  • 86

    Cooling air enters the fir-tree turbine blades though the

    base of the root.

  • 87

    Fir-Tree turbine blades attachment .

    allows slight movement

  • 88

    The space between two nozzle guide vanes forms

    a convergent duct in order to increase velocity.

  • 89

    the cooling air flows through the hollow nozzle vanes and rotor blades

    this method is known as Convection cooling

  • 90

    Blade Twist

    To ensure equal work done all over the blade length (root to tip)

  • 91

    Nozzle Guide Vanes Function

    direct gases in proper angle to first stage turbine nozzle

  • 92

    Nozzle Guide Vanes

    Cooling by ceramic coating and bleed air.

  • 93

    Creep is permanent elongation in rotor blades, resulting of

    thermal stress and high centrifugal force .

  • 94

    Most creep resistant blades are

    single structure blades

  • 95

    ACC cools turbine casing to

    reduce tip losses and improve efficiency in the cruise

  • 96

    Shrouded turbine rotor blades used

    to reduce vibration and improve air flow.

  • 97

    The efficiency of a turbine blade increases proportional, as its

    rotational speed increases

  • 98

    The nozzle guide vanes and at the rotor blades are cooled by the method of

    film cooling .

  • 99

    Running clearance on a turbine disk is kept to a minimum to reduce

    tip losses

  • 100

    advantage of an axial turbine is that it

    allows very high airflow which is needed to create the high thrust of modern engines