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7/21/2019 ME2121 - ME2121E Slides Chapter 1 (2014)
1/13
Mechanical Engineering,
NUS
Introduction for students who aspire to become a practicing Mechanical
Engineer. with a title, Er (by the Professional Engineers Board).
Thermodynamic functions of machines and cycles a key subject ofMechanical Engineering
Topics to be covered Review of fundamentals, definitions etc. (Tutorial #1),,
Properties of pure substances, state diagrams, how to use steamtables, temperature measurements and scale. (Tutorial #2)
First Law of thermodynamics, steady flow energy equations,
applications (Tutorial #3), Second Law of Thermodynamics, statements of 2nd Law, Clausius
inequality, Clausius Clapeyron equation, entropy, entropy increase.
(Tutorial #4).
ME2121- Thermodynamics
Chapter 1 1/ 9
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Mechanical Engineering,
NUS
Texts & References
Cengel YA and MA Boles, Thermodynamics: anengineering approach, 4th edition, McGraw Hill,2002
van Wylen GJ and RE Sonntag, Fundamentals ofclassical thermodynamics, John Wiley & Sons, 1993
Rogers GFC & YR Mayhew, EngineeringThermodynamics, Longmann, 1992
Engineering and Chemical Thermodynamics by MDKoretsky, Wiley, 2004 (Advance reading)
Thermodynamics and Transport properties of fluids (SIUnits) by GFC Rogers and YR Mayhew, Blackwell.
ME2121- Thermodynamics
Chapter 1 2/9
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Mechanical Engineering,
NUS
What is Thermodynamics?
A science that deals with the properties of matter and therelationship between key variables -energy, heat, work,temperature, enthalpy, entropy, etc.
Treats all matters behave in a continuum manner,
Based on simple postulates or laws, axioms forbehaviour of matters,
To quantify efficiency, useful effects (work), etc.
A tool to evaluate the viability of a machine or system To make investment decision on the thermo-economics
of projects, eg., micro-power plants, cooling and heatingplants, aeroplanes, fleet of vehicles, etc.
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Mechanical Engineering,
NUS
Historical background people associated with thermodynamics
ME2121- Thermodynamics
Chapter 1 4 / 9
1. Joseph Black (1728-1799)-Noted forhis fundamental work on latent and
specific heats and for his discovery
of carbon dioxide.
2. http://www.chem.gla.ac.uk/~alanc/dept/black.htm
1. Benjamin Thomson (1753-1814)noted for his early statement on
the 1st Law, disproved the
caloric theory of heat.
http://www.english.upenn.edu/Projects/knarf/People/rumford.html
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Mechanical Engineering,
NUS
ME2121- Thermodynamics
Chapter 1 5/9
Robert Mayer (1814-1878) reported
the conversion between heat and
work.
http://www.mhtl.uwaterloo.ca/courses/
me354/mayer.html
James P Joule (1818-1889) noted for
his experiments in heat, formulated
the amount of heat to produce a unit
of work- the Joule Law.
http://www.mhtl.uwaterloo.ca/courses/me354/joule.html
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Mechanical Engineering,
NUS
ME2121- Thermodynamics
Chapter 1 6/9
Sadi Carnot(1796-1832) noted for
the heat input to steam engine
and the work derived from it, laidthe foundation to 2nd Law (1824)
in the thesis, the motive of fire.
http://www.mhtl.uwaterloo.ca/courses
/me354/carnot.html
Rudolf Clausius (1822-1888) unified
the statements of 2nd Law
axioms of thermodynamics.
http://www.mhtl.uwaterloo.ca/courses/
me354/clausius.html
7/21/2019 ME2121 - ME2121E Slides Chapter 1 (2014)
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Mechanical Engineering,
NUS
ME2121- Thermodynamics
Chapter 1 7/9
Lord Kelvin (1824-1907) noted for the
absolute temperature scale.
Scottish Mathematician & physicist
http://www-groups.dcs.st-
and.ac.uk/~history/Mathematicians/
Thomson.html
JW Gibbs (1839-1903) noted for the
Gibbss law. First person to obtain
PhD in USA (Yale).
http://en.wikipedia.org/wiki/Josiah_Willar
d_Gibbs
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Mechanical Engineering,
NUS
Useful applications of Thermodynamics
Power plants electricity production
Internal Combustion engines work horse of our mode oftransportation,
Gas turbines air transportation, ships, etc.
http://www.geae.com/engines/commercial/genx/2b_fett.html
Compressors for air conditioning chillers, highpressurized air, etc.
Desalination plants multi-stage, adsorption, etc.
Biological processes oxygenation in blood streams,heart of animals, humans, etc.
Heat exchangers chillers, heaters, processes, reactors,
Separation reactors- chemical plants
ME2121- Thermodynamics
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Mechanism of Photosynthesis a thermodynamic
view point.
1. Fraction of useful wavelength of
solar spectrum = 0.25
2. Fraction of photons reaching the
leaves (containing chlorophyll) is
0.7 (70%).
3. Each photon of sunlight has 1.7
eV energy (1eV=1.609 x 10-19J)
4. I unit of glucose (plant matter) is
equivalent to 5 eV energy.However, the process of
achieving 1 unit of plant matter
requires 8 photons (due to
losses)
CO2 O2
H 2O
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Photosynthesis a thermodynamic process
that occurs in plants
10
06.035.07.025.0
)7.18()5(cos
eVxphotonsincidenttoeVegluinenergy
storedofamtoffraction
foilageinspectrumlightabsorbedoffraction
lightincidentfromeffectwavelengthusefuloffraction
esisphotosynth xx
chlorophyll Plant experiments:- 3744 Cal/g or 15665 J/g of glucose
(by EC Pielou The energy of nature)
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Kenaf plant known as a miracle plant for CO2 capture.
11
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CO2 capture by Kenaf Plants an excellent crop
12
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Mechanical Engineering,
NUS
Internal combustion engines
ME2121- Thermodynamics
Chapter 1 9/9
(http://en.wikipedia.org/wiki/Image:4-Stroke-Engine.gif(for engine)
http://www.dula.tv/watch.php?file=how-the-drinking-bird-works.flv (drinking bird)