I've bought the pdf and there is a ton to info to cover which may take a long time. Is it possible for you to narrow the last question down for me? I know I should have to work for it, as I'm sure you have, but any help would be appreciated. I'm wanting to get a general idea of what an...
Yes, good points and understood. The size and cost have to be practical. I'm asking these questions to have a better theoretical understanding of the process. I appreciate your input.
Thanks for the recommendation.
Off hand, do you have an estimate of about what max piston velocity starts to make the process significantly irreversible, or a velocity that could be approximated as reversible? Obviously, a shorter stroke would produce a slower max velocity for a given volume.
Yes, I meant heating in addition to the normal temperature increase during reversible adiabatic compression. Thanks for the clarification.
I know I can look this up and get into it but if you could provide an equation or direct me to a good source on the subject, I'd appreciate it.
Do you mean...
This "viscous dissipation" may be what I missed. Is this the cause of heating during irreversible adiabatic compression? If so, what are the limits here and how is it measured? You say move the piston very slowly, but how slow? Is the velocity of the piston movement simply relative to the...
To compress gas most efficiently at the lowest exit temperature (stagnation).
Yes, I understand that part, but it seems to me when comparing a reversible adiabatic process to an isothermal one, one isn't more efficient than the other. They are both reversible.
The pressure is higher in the reversible adiabatic case. Are you saying there is essentially no difference, one is not more wasteful than the other? If so, I understand your point. Still though, I suspect it matters how the gas was compressed which leads to the next question...
This may be...
Yes, higher than with cooling. But I’m comparing adiabatic processes, reversible and irreversible. The reversible case will result in a lower temperature for the same delivery pressure.
I don’t understand why cooling is more efficient. You’re not reusing the heat to compress more gas. You’re...
I apologize if if I haven't been able to describe what I'm trying to understand. Perhaps it would be easier if I asked a question like this:
There is a large flywheel spinning with a large mass and more than enough energy to continue for a while. I engage a clutch coupled to a cylinder/piston...
What I mean is that if our goal for a compressor is to have compressed air at it's highest pressure and lowest temperature, meaning a higher density, for a given cycle rate (rpm), a reversible adiabatic process is more efficient in converting the work to compressed air. Say you have reed valves...
Yes, I understand and that is a valid point, but before getting to that, I’m trying to understand how the piston motion affects the gas negating any heat transfer or heat from friction. How could a piston be driven to make the process truly reversible, or at least closer to it?
That I don’t know. I should have clarified that I’m assuming the process is adiabatic with no heat exchanger. I’m trying to understand the interaction between only the piston and gas which I suspect depends on it’s speed and how it’s driven. Would a faster moving piston (higher rpm) naturally...