Timeline for Quasi-static processes that are not reversible
Current License: CC BY-SA 4.0
8 events
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| Jun 29, 2023 at 14:51 | comment | added | LPZ | In this more detailed description, there are two relevant timescales: the homogenisation due to to conductivity and the relaxation time of equilibration with the thermostat. The quasi-static limit is obtained by the separating these scales, the former being taken to zero. | |
| Jun 29, 2023 at 14:47 | comment | added | LPZ | Yes, this isn't unusual for simplified model. The situation could be modelled as a solid of infinite thermal conductivity (for the temperature to be homogeneous so that the evolution is quasistatic) and Newton's law of cooling at the boundary (Robin boundary condition). Indeed, the creation of entropy is at the boundary as it should. | |
| Jun 29, 2023 at 14:20 | comment | added | Vincent Fraticelli | @LPZ Thanks for the additional comment ! With these assumptions, we would have a temperature discontinuity on the surface? In a more realistic model, we would have a strong gradient near the surface and the transformation would not be quasistatic? The entropy creation would be localized near the surface. | |
| Jun 29, 2023 at 12:48 | history | edited | LPZ | CC BY-SA 4.0 |
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| Jun 29, 2023 at 12:10 | comment | added | hyportnex | @VincentFraticelli why would LPZ's conclusion for pure thermal exchange be incorrect if it is indeed the case, as you have stated, that "it is easy to prove"? I for one have never seen a real proof for the general quasi-static case that does not assume the conclusion. It is not enough to prove that entropy production is 2nd order relative to temperature difference but that it is second order relative to its production by all other quasi-static changes. | |
| Jun 29, 2023 at 11:44 | comment | added | Vincent Fraticelli | I'm not sure your conclusion is correct ? It is easy to prove that the entropy created is second order with respect to the temperature difference. As a result, the entropy created does indeed tend towards 0 within the limits of a series of infinitesimal transformations. | |
| Jun 29, 2023 at 10:17 | comment | added | hyportnex | see, some more calculational details physics.stackexchange.com/questions/317690/… | |
| Jun 29, 2023 at 8:49 | history | answered | LPZ | CC BY-SA 4.0 |