Talk:Isentropic process

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[edit] Could be more understandable

I would add to the article the following explanation to make everything more easy for understanding.

Entropy balance for closed system: dS = dQ/T + dσ, where

 dS is entropy change for the system, 
 dQ/T is entropy generation due to heat transfer to/from the system
 dσ is entropy generation due to internal irreversibilities in the system

=>

S2-S1 = Q/T + σ By definition isentropic process is S2-S1 = 0. Therefore, the next statements easily follow:

1) Isentropic adiabatic process must be reversible:

  0 =     0     +  σ => σ=0 => reversible process
  (S1=S2) (Q=0)

2) Irreversible isentropic process must be NOT adiabatic:

  0       =  Q/T   +   σ      => σ = -Q/T 
  (S1=S2)    (!=0)     (!=0)     ( heat must be removed from the system, minus sign )

IMHO, it's always better to see formulas instead of verbal explanations..

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agree IlyaV 18:42, 28 October 2007 (UTC)