Cen54261ch07qxd 111803 957 am page 278 278

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: rreversible process. cen54261_ch07.qxd 11/18/03 9:57 AM Page 278 278 FUNDAMENTALS OF THERMAL-FLUID SCIENCES or 2 1 Q T 1 Q T 2 0 int rev The second integral in the above relation is recognized as the entropy change S1 S2. Therefore, 2 1 Q T S1 S2 0 which can be rearranged as Q T 2 S2 S1 1 (7–7) It can also be expressed in differential form as dS Q T (7–8) where the equality holds for an internally reversible process and the inequality for an irreversible process. We may conclude from these equations that the entropy change of a closed system during an irreversible process is greater than the integral of dQ/T evaluated for that process. In the limiting case of a reversible process, these two quantities become equal. We again emphasize that T in these relations is the absolute temperature at the boundary where the differential heat dQ is transferred between the system and the surroundings. The quantity S S2 S1 represents the entropy change of the system. For a reversible process, it becomes equal to 21 dQ/T, which represents the entropy transfer with heat....
View Full Document

Ask a homework question - tutors are online