15.6 Turbine Section (Level 1, 3 Questions) Flashcards by Dylan Sinclair

What does the turbine transform a portion of the kinetic energy of the exhaust gases into?
A. Electrical energy
B. Heat energy
C. Mechanical energy

C. Mechanical energy

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What components can the turbine stages drive?
A. Electrical buses and fuel pumps
B. Compressor, propeller, and shaft
C. Avionics and cabin pressurization

B. Compressor, propeller, and shaft

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What are the two types of turbines on gas turbine engines?
A. Dual-flow and cross-flow
B. Radial flow and axial flow
C. Rotary and static flow

B. Radial flow and axial flow

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What is always the first main component of a turbine?
A. Rotor blades
B. Combustion chamber
C. Turbine nozzle guide vanes

C. Turbine nozzle guide vanes (stators)

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What is a radial flow turbine?
A. A turbine with flow perpendicular to rotation
B. A single-stage turbine used on small gas turbines like the APU
C. A multi-stage turbine with high thrust output

B. A single-stage turbine used on small gas turbines like the APU

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What is an axial flow turbine?
A. A turbine used only in helicopters
B. A turbine with airflow entering at a right angle
C. A turbine that allows high airflow and is used in modern engines

C. A turbine that allows high airflow and is used in modern engines

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What is a turbine called when rotation is caused only by the impact of the gas flow?
A. Reaction turbine
B. Centrifugal turbine
C. Impulse turbine

C. Impulse turbine

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How many types of turbine blades are there?
A. One
B. Two
C. Three

C. Three

(Impulse configuration, Reaction configuration, Reaction-impulse configuration)

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What causes the turbine to rotate?
A. The rotation of the fan
B. The impact of gas flow on the turbine rotor blades
C. A motor-driven shaft

B. The impact of gas flow on the turbine rotor blades

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What does an impulse turbine blade configuration do?
A. Uses rotor blades to reduce pressure
B. Converts all pressure energy to kinetic energy in nozzle guide vanes
C. Accelerates gas in the turbine rotor

B. Converts all pressure energy to kinetic energy in nozzle guide vanes

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What is a characteristic of reaction turbine blades?
A. Require extremely high gas velocity
B. Change direction of gas without changing pressure
C. Experience impulse force only

B. Change direction of gas without changing pressure

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B. Converts all pressure energy to kinetic energy in nozzle guide vanes

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What does a reaction-impulse turbine blade do?
A. Combines impulse and reaction forces
B. Works with only a single force at the tip
C. Creates force only at the root

A. Combines impulse and reaction forces

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Why are many turbine blades cast as a single crystal?
A. To reduce engine weight
B. To improve fuel consumption
C. To improve strength and heat resistance

C. To improve strength and heat resistance

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Why are many turbine blades cast as a single crystal?
A. To reduce engine weight
B. To improve fuel consumption
C. To improve strength and heat resistance

C. To improve strength and heat resistance

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What helps keep turbine blades and inlet nozzles cooler?
A. Titanium outer shells
B. Heat barrier coatings and airflow cooling
C. Internal oxygen circulation

B. Heat barrier coatings and airflow cooling

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Why are turbine blades made impulse-type at the roots and reaction-type at the tips?
A. To increase centrifugal force
B. To improve rotational speed only
C. To maintain a constant blade exit pressure

C. To maintain a constant blade exit pressure

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What causes high centrifugal loads on the turbine wheel?
A. Low gas pressure
B. High rotational speed
C. Large blade size

B. High rotational speed

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What happens when turbine blades are installed onto the disc?
A. The disc becomes part of the combustion chamber
B. The disc becomes the turbine wheel
C. The disc begins to rotate independently

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B. The disc becomes the turbine wheel

What is the purpose of the disc in the turbine assembly?
A. It stores fuel
B. It acts as a heat sink
C. It anchors the blades

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C. It anchors the blades

What allows the turbine blades to transmit energy to the rotor shaft?
A. The disc is bolted or welded to the shaft
B. The blades are hollow
C. The shaft is cooled

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A. The disc is bolted or welded to the shaft

Why is cooling air bled onto the face of the disc?
A. To prevent warping
B. To relieve thermal stresses
C. To cool the combustion chamber

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B. To relieve thermal stresses

What do the grooves in the disc rim allow?
A. More fuel to be stored
B. The attachment of turbine blades
C. Airflow into the turbine

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B. The attachment of turbine blades

What is the more common method of attaching the shaft to the disc?
A. Welding
B. Gluing
C. Bolting

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C. Bolting

What kind of coupling is primarily used for centrifugal compressor engines? A. Threaded B. Splined C. Welded

B. Splined

What is the most common design for attaching turbine blades? A. Bulb B. Fir tree C. Latch

B. Fir tree

What does the peening method of blade retention involve? A. Applying glue to the blade B. Flowing disc metal into a blade notch C. Welding the blade to the shaft

B. Flowing disc metal into a blade notch

What is a feature of the blade root stop retention method? A. Blades are retained by magnetic force B. Blade can be inserted and removed in one direction only C. Blade locks into place with a spring

B. Blade can be inserted and removed in one direction only

What does the stator consist of in a turbine assembly? A. Compressor blades and outlet vanes B. Nozzle and inlet guide vanes C. Fan blades and stator shaft

B. Nozzle and inlet guide vanes

What connects the turbine blades (rotor) in the turbine assembly? A. Compressor fan B. Inlet guide ring C. Turbine shaft

C. Turbine shaft

What is another name for the stator element? A. Turbine outlet vanes B. Nozzle diaphragm C. Rotor hub

B. Nozzle diaphragm

Where are the turbine inlet nozzle vanes located? A. Forward of the combustion chamber B. Directly aft of the combustion chamber C. Inside the fan casing

B. Directly aft of the combustion chamber

What does the turbine inlet nozzle assembly consist of? A. Inner and outer blades B. Rotor and stator shrouds C. Inner and outer shroud

C. Inner and outer shroud

Why must nozzle vanes be constructed to allow for thermal expansion? A. To prevent airflow separation B. To avoid distortion or warping C. To increase blade speed

B. To avoid distortion or warping

How is thermal expansion of the turbine nozzles absorbed? A. By air cooling ducts B. By reinforced turbine shafts C. By loose assembly of the inner and outer vane shrouds

C. By loose assembly of the inner and outer vane shrouds

How can vanes be fitted into the inner and outer shrouds? A. Threading or gluing B. Welding or riveting C. Casting or stamping

B. Welding or riveting

What are two common methods used to inspect turbine discs and blades? A. X-ray and ultrasound B. Visual and dye penetrant C. Magnetic resonance and eddy current

B. Visual and dye penetrant

What must be done if cracks are found on the turbine disc? A. Blend and repaint the area B. Monitor in future inspections C. Replace the disc and turbine rotor

C. Replace the disc and turbine rotor

What is the correct action for slight pitting caused by FOD on a turbine disc? A. Replace the disc immediately B. Blend by stoning and polishing C. Drill out the pits

B. Blend by stoning and polishing

What tools are used to inspect turbine blades for stress cracks and deformation? A. Endoscope and micrometer B. Strong light and magnifying glass C. Thermal camera and scope

B. Strong light and magnifying glass

If stress cracks or deformation are found on the leading edges of the first-stage turbine blades, what condition is suspected? A. Corrosion B. Over-temperature C. Low oil pressure

B. Over-temperature

What is creep in turbine materials? A. A crack from vibration B. A thermal shock failure C. A slow structural deformation at the molecular level

C. A slow structural deformation at the molecular level

What factor increases creep in turbine blades? A. Lubrication B. Altitude C. Temperature

C. Temperature

What might scoring on the turbine case indicate? A. Blade contamination B. Blade length out of tolerance C. Improper lubrication

B. Blade length out of tolerance

What must be done before removing turbine blades for inspection? A. Clean them with solvent B. Heat them with a torch C. Number them

C. Number them

After removal, turbine blades must be reinstalled in: A. Any slot B. Opposite positions C. The same position they were removed from

C. The same position they were removed from

15.6 Turbine Section (Level 1, 3 Questions) Flashcards

(46 cards)