Discussion Overview
The discussion revolves around deriving the entropy values for the Otto cycle, specifically focusing on the isentropic compression phase where it is proposed that the entropy at states 1 and 2 (s1 and s2) are equal. Participants explore methods to calculate these entropies using temperature and pressure data, as well as the ideal gas properties.
Discussion Character
- Homework-related
- Technical explanation
- Conceptual clarification
Main Points Raised
- One participant inquires about deriving the entropy values at the isentropic compression phase of the Otto cycle, given the compression ratio and other state variables.
- Another participant questions the necessity of determining absolute entropies and their relevance in the context of the problem.
- There is a suggestion to use the air properties table to find entropies for states 1 and 2 based on known temperatures and pressures.
- One participant confirms the assumption that s1 equals s2 due to the isentropic nature of the process and seeks to derive s3 using a specific equation.
- Concerns are raised regarding the air table typically providing relative entropy rather than absolute values, prompting a reminder to check the reference state used in the table.
- Participants confirm the validity of the equation set up to solve for entropy at state 3.
Areas of Agreement / Disagreement
Participants generally agree on the assumption that s1 equals s2 during the isentropic process, but there is no consensus on the absolute values of entropy or the necessity of determining them. Multiple viewpoints regarding the use of the air properties table and its reference states are present.
Contextual Notes
Participants note the limitation that the air properties table may not provide absolute entropy values, which could affect the calculations and interpretations of the results.
