TataKelola dan KamSiber Kecerdasan Buatan v022.pdf
et-entropy-180304054721 (1).pdf
1.
2.
3. The Entropy is a thermodynamic property of a
working substance and serves as a valuable tool in
the second law analysis of engineering devices.
Entropy is a function of a quantity of heat which
shows the possibility of conversion of that into
work.
Entropy is a thermodynamic property; it can be
viewed as a measure of disorder i.e. More
disorganized a system the higher its entropy.
4. The Clausius Theorem is a mathematical
explanation of the Second Law of
Thermodynamics.
Also referred to as the “Inequality of Clausius”,
the theorem was developed by Rudolf Clausius
who intended to explain the relationship
between the heat flow in a system and the
entropy of the system and its surroundings.
The Clausius Theorem was first published in
1862in Clausius’ sixth memoir, “On the
Application of the Theorem of the Equivalence
of Transformations to Interior Work”.
5.
6. “ When a system undergoes a complete cyclic
process, the integral of around the cycle is less
than zero.”
Mathematically : ( ) ≤ 0
δQ is energy flow into the system due to heating
and T being absolute temperature of the body
when that energy is absorbed.
The following equation must be found true for
any cyclical process that is possible, reversible or
not.
7. Consider a reversible engine R and irreversible engine I
working between two thermal reservoirs at temperatures TH
and TL.
Efficiency of reversible engine is :
where δQH = heat added, δQL = heat rejected.
Efficiency of irreversible engine is :
We know that efficiency of reversible engine is more than
that of irreversible engine under same temperature limit.
∴ ηR > ηI ∴ ( )R > ( )I
∴ ( )R > ( )I (∵ for reversible engines )
8. ∴ ( ) < ( )I
∴ ( )I < ( )I
∴ ( )I - ( )I < 0
We know that, heat added ( δQH ) should be positive
and heat rejected( δQL ) should be negative.
∴ ( )I - (- )I < 0
9. ∴ ( )I + ( )I < 0
Considering complete original irreversible cycle :
∴
∴ ∮ ( ) < 0 for an irreversible cycle.
According to Clausius Theorem ∮ = 0 for reversible
cycle.
Combining results for reversible and irreversible cycle,
we get :
This expression is known as
Clausius Inequality.
10.
11. On a T-S diagram, the area under the
process curve represents the heat transfer
for internally reversible processes.
13. Mollier diagram: The h-s diagram
For adiabatic steady-flow devices, the vertical
distance Δh on an h-s diagram is a measure of
work, and the horizontal distance Δs is a
measure of irreversibility's.