Heat injection and work during Rankine cycle

AI Thread Summary
The Rankine cycle includes two adiabatic and two isobaric processes, but the work done during isobaric processes is often considered negligible. This is because, during these processes, heat is added or removed at constant pressure, leading primarily to changes in volume rather than significant work output. Most of the heat energy is used for vaporization or condensation, which does not contribute to work in the traditional sense. The discussion also touches on the relevance of the first law of thermodynamics in open systems, suggesting that understanding these principles can clarify why work is not emphasized during isobaric processes. Overall, the focus is on the relationship between heat transfer and work in the context of the Rankine cycle.
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I have been researching the Rankine cycle. I know that it consists of two adiabatic and two isobaric processes. However, I'm not entirely sure why we ignore the work done during the isobaric processes (this seems to be the case in the analysis I'm looking at). Is that because the work done there is simply the work that the steam does to make room for itself? (and vice versa)
 
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In these processes heat is just being added or removed at constant pressure . Where is there any physical activity that results in work being done ?
 
Nidum said:
In these processes heat is just being added or removed at constant pressure . Where is there any physical activity that results in work being done ?
You add heat and pressure is kept constant, i.e. volume increases. That is usually the physical process that results in work being done. But here most of the heat goes into vaporization/condensation. Is this why we say that there is no work done during these processes?
 
Are you familiar with the open system (control volume) version of the 1st law of thermodynamics?
 

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