Is a Closed, Adiabatic Device Feasible For Work With Steam?

[Nah346]

2. A closed, adiabatic device claims to derive useful work by expanding 1 kg of steam from 500 C and 20 bar to 100 C and 1 bar. Do you believe this claim? Assume steam is a real fluid following the steam tables in Appendix A.III.

 

[rude man]

"Adiabatic"; what does that tell you about entropy change?

 

[Nah346]

"Adiabatic" indicates that there is No change in entropy due to heat transfer. Therefore that would eliminate the (SQ/T) and leave us with (S2-S2 = Sgen)

 

[rude man]

"Adiabatic" indicates that there is No change in entropy due to heat transfer. Therefore that would eliminate the (SQ/T) and leave us with (S2-S2 = Sgen)

Yes, so go to your tables and find out if s has or has not changed between your two given states.