3.6
3.6.1
Dry steam?
Introduction
In this section we continue to investigate the phenomena of phase change, returning again to the process of vapourisation.
In this section we shall see how we might describe the quantity of vapour formed during the vapourisation process and how we might use this in calculations.
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Terms
Be able toBy the end of this section you should be familiar with terms such as:
Saturated liquid, saturated vapour
Mixture quality
Evaluate the properties of steam Carry out simple calculations to determine the quantity and quality of steam produced
3.6.2
Dry steam?
How do you make electricity from coal?
Steam power station
Everyone is familiar with the sight of power station cooling towers.
Effective Digital Presentations, produced this incredible 3D animation to show how a coal fuelled power plant produces electricity. The video was produced specifically for FirstEnergy Corp. in the USA. This is a fully 3D rendered and animated video.
Pay particular attention to what occurs inside the boiler where liquid water is heated to produce high pressure steam.
3.6.3
Dry steam?
Pause for thought
Quality of the steam?
High pressure steam produced
Is there remaining liquid?
The key process in side the boiler of a coal power station
Coal power station boiler
In the video we were introduced to the whole cycle of generating power from coal in a power station. The key process occurs inside the boiler where liquid water is heated to produce high pressure steam.
Is all the liquid converted to vapour - would this be a problem if liquid were to remain?
We need to determine the “quality” of the steam!
3.6.4
Dry steam?
Screencast
Outline
In this unit we will continue to investigate the phenomena of phase change, returning again to the process of vaporisation. We will see how we might describe the quantity of vapour formed during the vaporisation process and how we might use this in calculations.
We will review the definitions of a saturated liquid, a saturated vapour and a superheated vapour.
3.6.5
Dry steam?
Review Questions
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Referring to the material presented in this section, can you answer the following questions -
What is the definition of a saturated liquid?
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Referring to the material presented in this section, can you answer the following questions -
What is the definition of a saturated vapour?
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Referring to the material presented in this section, can you answer the following questions -
What is the definition of a superheated vapour?
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Referring to the material presented in this section, can you answer the following questions -
What does the term “saturated mixture” refer to?
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Referring to the material presented in this section, can you answer the following questions -
What does “quality” refer to, and what is the allowable numerical range?
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Referring to the material presented in this section, can you answer the following questions -
Why are the subscripts “f” and “g” employed for specific volume?
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Referring to the material presented in this section, can you answer the following questions -
What does the NIST database allow you to do?
