Steam Turbines Part A Flashcards
How hot can turbines get?
1000 F/ 538 C
What is a Sentinel Valve?
A warning whistle for people around Turbines
Is a Sentinal Valve used to relieve or reduce pressure.
Neither
What are some ways to detect leaks on a turbine?
Thermography and ultrasonic acoustic equipment
What must you do if an overspeed trip happens while operating?
Immediately leave the building
What type of combustion engines do Steam Turbines harness?
External Combustion Engine
What is an External Combustion Engine?
A heat engine that uses heat from fuel comsumed outside the turbine cylider.
How does a turbine work?
A heat engine uses heat from fuel consumed outside the turbine cylinder. Energy released by steam drives the turbine blade, which in turn moves the rotor and produce useable rotational energy.
What is Newton’s Third Law
For every action, there is an equal and opposite reaction.
Where is Bernoulli’s Principle used in a Steam Turbine?
In the steam turbine nozzles and reaction blades.
What operational steam turbine types are there?
Impulse and Reaction
What type of turbine is this?
Impulse
What type of turbine is this?
Reaction
What type of blades are these?
Impulse Blades
What type of blades are these?
Reaction Blades
What is Enthalpy
The total energy derived from heat, weight, pressure and velocity.
Where is Enthalpy used?
Where steam is relased against the turbine blades.
How is Steam harnessed in Impulse Turbines
Nozzles direct the steam into impulse blades which then direct the steam in the opposit direction. These impulse blades are pushed and turn the rotor.
Is there a pressure drop across Impulse Blading?
No, there is no change in the space between the entry and exit through the blading.
How much axial thrust is developed on small impulse turbines? Why?
- Minimal
- There is no pressure drop
Is there pressure or velocity drop in fixed guide blades?
No
What is developed in Reaction Blade Turbines?
Axial thrust because of pressure drop.
- What do reaction blades look like?
- What do reaction blades harness more of then Impulse Blades?
- Pressure
Do reaction Steam Turbines require more blades? Why?
Yes because the pressure drop is small across the each row of blades.
What are the most common ways to attach blades to the rotor in turbines?
- Dovetail method
- Fir Tree method
What is wire lacing?
A means to stiffen and dampen vibratation caused on large blades which dont use shrouds.
They replace shrouds.
Are rotors statically and dynamically balanced?
- Yes, straight from the manufacturer.
What is a 1st critical?
What should you do when you reach this?
- One of a turbines critical speeds where the rotor becomes very unstable due to vibration.
-Get the turbine through that speed as quickly as possible.
What does steam go through right before hitting the blades?
Nozzle Ring
Do reaction blades get longer or shorter as they progress from row to row?
Longer to accomidate stream expansion throughout the turbine.
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What is this and label it.
Carbon Seal
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B) false; You must block in and drain many other sources of potential energy, not just steam.
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B) false; A steam turbine is an external combustion engine.
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B) false; Impulse-type blades (buckets) are concentric and their tips are parallel to the shaft.
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B) false; A reaction occurs because of the pressure drop across the moving reaction blades and the steam pushes on the blades as they leave. Reaction blades also witness an impulse from the steam changing direction as it passes through the blades.
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B) false; It serves as a warning and does not significantly reduce pressure.
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B) false; They prevent steam from leaking out of the turbine.
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B) false; The steam tends to leak around the periphery of the blades instead of passing through them. The clearances between the tips of the blades and the casing have to be kept to a minimum.
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B) false; The largest blades are at the low-pressure end.
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A)
