3. Reversible (Carnot) Heat engine
Is a hypothetical engine that operates on the reversible cycle
Named After Nicolas Carnot
Doesn’t Violate the first law
Violate the second law
Violation can be easily detected by Entropy S
The Carnot engine model was mathematically elaborated Nicolas Carnot
upon by Rudolf Clausius in the 1850s and 60s from which 1796-1832
the concept of entropy emerged. France
Simulation
Dr.Khaled S. Al-zahrani
4.
Reversible Process
First Law
Second Law
Q ?
Dr.Khaled S. Al-zahrani
5. First Law
Some process can not take place in real life but yet apply to the 1st law
Provides no restriction over the process direction
Second Law
Does not apply to such process
Gives Direction to the energy follow
Indicates the energy Quality
Provides accurate evaluation of any engineering process.
Provides a theoretical limit of any engineering process.
Dr.Khaled S. Al-zahrani
6. Second Law Statements:
Clausius statement
No process is possible whose sole result is the transfer of heat from
a body of lower temperature to a body of higher temperature
Kelvin statement
No process is possible in which the sole result is the absorption of
heat from a reservoir and its complete conversion into work.
Dr.Khaled S. Al-zahrani
7. Entropy S
Entropy is
a thermodynamic property that can be used to determine the energy
available for useful work in a thermodynamic process
a measure of the disorder of a system.
𝑄
Δ𝑆 =
𝑇
the heat added per unit temperature and
has the units of Joules/Kelvin (J/K)
In any cyclic process the entropy will either increase or remain the same
according to the second law of thermodynamic
Dr.Khaled S. Al-zahrani