Adiabatic irreversible process vs adiabatic reversible

In summary, the conversation discusses the relationship between entropy and reversible processes, specifically in an adiabatic system. The speaker believes that in a reversible process, there must be some heat flow from the initial state A to the final state B in order to account for the positive change in entropy.
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cianfa72
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adiabatic irreversible vs adiabatic reversible processes between two given thermodynamic states
Hi,

consider an adiabatic irreversible process carrying a thermodynamic system from initial state A to final state B: this process is accompanied by a positive change in system entropy (call it ##S_g##). Then consider a reversible process between the same initial and final system state. Such reversible process could be adiabatic itself ?

I believe not because the exceeding entropy between final and initial state (that are the same regardless the process) has to be transferred out to the surrounding by means of heat "crossing" the boundary of the system itself.

Does it make sense ? Thanks
 
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Yes. Since ##\Delta S = \int_A^B \frac{dQ_{rev}}{T}##, if ΔS > 0 then dQrev cannot be zero throughout: ie. there must be some heat flow during the reversible process from A to B

AM
 
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1. What is the difference between adiabatic irreversible process and adiabatic reversible process?

Adiabatic irreversible process is a thermodynamic process that occurs without any heat exchange with the surroundings and involves irreversible changes in the system. On the other hand, adiabatic reversible process is a thermodynamic process that occurs without any heat exchange with the surroundings and involves reversible changes in the system.

2. How do adiabatic irreversible and adiabatic reversible processes differ in terms of entropy change?

In adiabatic irreversible process, the entropy of the system increases due to irreversible changes, whereas in adiabatic reversible process, the entropy of the system remains constant as the changes are reversible.

3. Which process is more efficient - adiabatic irreversible or adiabatic reversible?

Adiabatic reversible process is more efficient as it involves reversible changes and does not result in any energy loss, whereas adiabatic irreversible process involves irreversible changes and results in energy loss.

4. Can adiabatic irreversible process be reversed to become adiabatic reversible?

No, adiabatic irreversible process cannot be reversed to become adiabatic reversible as it involves irreversible changes in the system.

5. What are some real-life examples of adiabatic irreversible and adiabatic reversible processes?

A common example of adiabatic irreversible process is the expansion of a gas in an engine, where heat is not exchanged with the surroundings and the changes are irreversible. An example of adiabatic reversible process is the compression and expansion of a gas in a piston-cylinder system, where heat is not exchanged with the surroundings and the changes are reversible.

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