Thermodynamics for
engineers
“Thermodynamics is a funny subject. The first
time you go through it, you don’t understand it at all. The second time you go
through it, you think you understand it, except for one or two small points.
The third time you go through it, you know you don’t understand it, but by that
time you are so used to it, it doesn’t bother you any more.”
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The
word thermodynamics originates from the Greek words therme
(heat) and dynamis (force). It is the branch of
physical science that studies the physical properties of macroscopic systems of
matter and energy including any spontaneous conditions, modifications or
interactions that may occur between them. In other words, it deals with the
mechanical actions or relations of heat. This science utilizes many variables
such as pressure, volume, density, temperature and specific heat, to facilitate
the description of macroscopic systems; the description of the behavior of an
object and its relation to its environment.
Thermodynamics
is considered one of the most important branches of physics due to the fact
that it involves fundamental laws and principles that relate to all the
different fields of engineering and science. It began developing in the XIX
century when the study of heat and its ability to produce mechanical work
became of great interest. However, the first thermodynamic term employed was
"temperature" in the VII century. Galileo, an Italian physicist and
astronomer, invented the first primitive thermometer. Then, Jean Ray and the
grand duke Ferdinand II of
Soon, many questions raised in the thoughts of a
selected few. Questions concerning the transferring of energy from one body to
another. Was it temperature that was being passed? This was a dubious inquiry
that many hoped to answer. The best absolution was found in the study of a new
science established by Joseph Black in 1770 called the calorimetry. It is the
science of measuring quantities of heat expressed in calories. The calorimeter
was a stirring device used to measure the amount of heat of a substance. This
new science was based upon many postulates established by Black that were
later, toward the end of the XVIII century, contradicted by an American
colonial physicist and engineer, Benjamin Thompson. Nearly half a century,
James Prescott Joule, an English physicist, later presented more refined
theories.
Joule founded the first law of thermodynamics in the 1840s by demonstrating
that the quantity of work necessary to cause a given change of state is
independent of the type of work (electric, mechanical, etc.), the method of
delivering or the rate of doing work. He also concluded that work could be
converted into heat and heat into work.
Sadi Carnot, a French engineer who had created the Carnot engine in 1824, introduced the concept of the Carnot cycle. This conception distinguished the
interactions of systems from the modifications of their states. In 1850, Rudolf
Julius Clausius, a German physicist and mathematician
who had enunciated two laws and contributed to the expansion of the study of
this science, was intrigued by Carnot's notion.
Consequently, it came to assertion that his principle is a postulate and, as a
result, it became the second law of thermodynamics. Although in 1849 William
Thomson, also known as Lord Kelvin, announced that there was a conflict between
the conclusions carried out by Joule and the arguments on caloric Clausius settled this dilemma a few years later.
He established a property
called entropy, which was included it in the second law and redefined the first
and second law more explicitly.After the flourishing
of this new science, Lord Kelvin's interest in the study of temperature had
grown. He, inclusively, instituted various definitions for thermodynamic
temperature scales named after him. Not long after, a physicist of
Throughout
the years, many other ingenious European and American mathematicians and
physicist such as J. Willard Gibbs, Max Planck and Henri Poincaré, contributed
notions and theorems that were very much valuable for the enhancement of the
study of thermodynamics. In the XVIII century, in 1918, a Nobel Prize winning
German chemist, Walther Nernst, stated the Nernst theorem, which became the third law of
thermodynamics.
Click the following links
to understand the subject of thermodynamics:
Physics of Thermodynamics
Technology
First experiments- Heron
, Guericke
Steam engines- Papin Savery Newcomen Watt
Steam
trains Steam
cars Steam
ships Stirling engine
Combustion engine- Huygens
Gas
engines Otto
engine Multiple-cylinder
2-stroke
engine Diesel
engine Wankel
engine Steam
turbines Gas
turbines
Inventors
Heron
Guericke Newcomen Watt
Carnot Diesel
Wankel
Activities
Cubic
capacity Guericke p-V
Diagrams Sound
Animations
A must see for Thermo Engineers
Slide Show –for the examples of thermodynamics systems
Daemons - smart thermodynamic calculators
Map-for advanced user
VT- Explore Virtual Thermo, a multi-media presentation of how thermodynamic systems work.
One requires Internet Explorer (IE) 5+ or Netscape
Navigator (NN) 6.5+ with Java, Macromedia Flash, and Adobe Acrobat Reader
plug-ins.
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