Chp1 Introduction Flashcards

1
Q

Why must heat be added to working fluid between compressor and turbine?

A

So that the turbine can produce added work

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2
Q

What are the three biggest effects on turbine efficiency?

A

“1) Compressor ratio

2) Turbine inlet temperature
3) Component efficiencies”

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3
Q

Out of these three, which has the biggest effect?

A

Compressor ratio

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4
Q

Where would you add an intercooler and why?

A

In between compressors to reduce compressor work

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5
Q

Where would you add a reheater and why?

A

In between turbines, to increase turbine work

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6
Q

What’s the difference between single shaft and twin shaft?

A

Single shaft good for fixed rotational speed (i.e. generators), twin shaft good for variable speed (i.e. planes or ships)

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7
Q

Why are reheaters and intercoolers effective?

A

Work required is directly proportional to inlet temperature.

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8
Q

One characteristic of multi-spool?

A

Mechanically independent but aerodynamically related

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9
Q

What is a turbojet?

A

Turbine powers just compressor; rest of gas is nozzle’d into a propulsion jet

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10
Q

What is a turboprop?

A

Secondary turbine powers propeller; mix of exhaust gas and propeller

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11
Q

What is a turbofan?

A

Mix of turbojet and turboprop; LP compressor bypasses some air into annular flow

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12
Q

When is a turboprop effective?

A

Lower speed aircraft

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13
Q

When is a turbojet effective?

A

Not so much anymore; superseded by turbofan

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14
Q

When is a turbofan effective?

A

High subsonic speeds; low noise

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15
Q

What are three reasons aircraft and industrial gas turbines are so different?

A

“1) Industrial expected 50 000 hours

2) Size and weight important for aircraft
3) Kinetic energy important for aircraft”

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