Entropy -- prove it increases for irreversible process

In summary, the conversation discusses the concept of entropy rate balance for control volumes and how it applies to the irreversible process of throttling. The main focus is on proving that (S2-S1) is greater than zero in this process. Chet also mentions a previous thread where this question was addressed, and asks for clarification on any remaining doubts or disagreements.
  • #1
jangseok seo
7
0
hi all,

upload_2015-5-20_2-14-30.png

this is Entropy Rate Balance for Control Volumes.

in the case of throttling process,


upload_2015-5-20_2-17-43.png
.throttling process is irreversible process, so (S2- S1) must be greater than zero.

what i want to know is to prove that (s2-s1) is greater than zero.

Thank you in advance.
 

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  • #2
jangseok seo said:
hi all,

View attachment 83647
this is Entropy Rate Balance for Control Volumes.

in the case of throttling process,


View attachment 83652.throttling process is irreversible process, so (S2- S1) must be greater than zero.

what i want to know is to prove that (s2-s1) is greater than zero.

Thank you in advance.
I thought we had already answered this question in the following thread: https://www.physicsforums.com/threads/throttling-process.814170/#post-5112310. Were you dissatisfied with the explanation given in that thread? If so, what was it that you disagree with?

Chet
 

FAQ: Entropy -- prove it increases for irreversible process

What is entropy?

Entropy is a measure of the disorder or randomness in a system. It is often described as the tendency of a system to move towards a state of equilibrium.

How is entropy related to irreversible processes?

In an irreversible process, there is a net increase in the overall disorder of the system. This increase in disorder leads to an increase in entropy.

Can you give an example of an irreversible process?

An example of an irreversible process is the burning of a piece of wood. In this process, the wood is converted into ash and smoke, and the overall disorder of the system increases.

What is the mathematical equation for entropy?

The mathematical equation for entropy is ΔS = Q/T, where ΔS is the change in entropy, Q is the heat transferred, and T is the temperature.

How can we prove that entropy increases for irreversible processes?

We can prove that entropy increases for irreversible processes by using the Second Law of Thermodynamics, which states that the total entropy of a closed system always increases over time. This can be observed and measured in various physical and chemical processes, providing evidence for the increase of entropy in irreversible processes.

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