[L3]_AERODYNAMICS OF TURBINE BLADES

Question 1

ENGY-688

In the context of Aerodynamics, what is meant by the term ‘Aero’?

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Answer 1

The Interaction of Air Movement

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Question 2

ENGY-688

What is the combined definition of Aerodynamics?

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Answer 2

The study of motion for air and fluids on a body

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Question 3

ENGY-688

What is the cross section length of an airfoil?

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Answer 3

Chord

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Question 4

ENGY-688

What shape is a positive Camber?

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Answer 4

Convex

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Question 5

ENGY-688

What percentage of the chord length is the maximum thickness?

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Answer 5

30%

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Question 6

ENGY-688

Where is the center of gravity of an airfoil located?

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Answer 6

Mean Camber Line

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Question 7

ENGY-688

What is the most forward point of the mean camber line?

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Answer 7

The Leading Edge

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Question 8

ENGY-688

What is the most rearward point of the mean camber line?

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Answer 8

The Trailing Edge

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Question 9

ENGY-688

What does NACA stand for?

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Answer 9

National Advisory Committee for Aeronautics

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Question 10

ENGY-688

What is a characteristic of the first two digits being zero in an airfoil?

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Answer 10

Symmetrical Airfoil

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Question 11

ENGY-688

What is the Coanda Effect?

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Answer 11

Fluid jet stream attachment

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Question 12

ENGY-688

What type of airfoils do wind turbine blades use?

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Answer 12

Non-Symmetrical (cambered)

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Question 13

ENGY-688

Do air molecules meet at the trailing edge of blade?

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Answer 13

No

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Question 14

ENGY-688

What happens to the speed of air on the upper camber?

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Answer 14

Increases

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Question 15

ENGY-688

What happens to pressure as the velocity of air increases?

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Answer 15

Pressure Decreases

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Question 16

ENGY-688

Define aerodynamic force (F) direction as it relates to an airfoil

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Answer 16

Perpendicular to the Airfoil

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Question 17

ENGY-688

How do you calculate aerodynamic force?

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Answer 17

F = Pnet * A

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Question 18

ENGY-688

How is drag force oriented in relation to the wind?

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Answer 18

Parallel to wind direction

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Question 19

ENGY-688

What does α (alpha) represent?

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Answer 19

Angle of Attack

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Question 20

ENGY-688

In the equations, what does the symbol δ represent?

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Answer 20

Air Density

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Question 21

ENGY-688

What aerodynamic forces can act on an airfoil?

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Answer 21

Lift and Drag

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Question 22

ENGY-688

Under what condition does Lift become reversed?

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Answer 22

Negative Angle of Attack

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Question 23

ENGY-688

What happens when the critical angle of attack is surpassed?

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Answer 23

Stall

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Question 24

ENGY-688

What does ωblade represent?

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Answer 24

Rotational speed of the blade

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Question 25

# ENGY-688 What happens to angle of attack (α) when pitch angle (β) is increased? ## Footnote [L3]

Answer 25

α is reduced ## Footnote [L3]

Question 26

# ENGY-688 What does TSR stand for? ## Footnote [L3]

Answer 26

Turbine Blade Tip Speed Ratio ## Footnote [L3]

Question 27

# ENGY-688 What is the relationship between number of blades and TSR? ## Footnote [L3]

Answer 27

Fewer blades, higher TSR ## Footnote [L3]

Question 28

# ENGY-688 What is the tip velocity? ## Footnote [L3]

Answer 28

Maximum speed of rotor tip ## Footnote [L3]

Question 29

# ENGY-688 What issues arise from a high TSR? ## Footnote [L3]

Answer 29

Turbulent air and failures ## Footnote [L3]

Question 30

# ENGY-688 What is the consequence of elevated TSR on a structure? ## Footnote [L3]

Answer 30

Structural Failure ## Footnote [L3]