Unformatted text preview: ergy interaction that is
accompanied by entropy transfer is heat transfer, and an energy interaction
that is not accompanied by entropy transfer is work. That is, no entropy is exchanged during a work interaction between a system and its surroundings.
Thus, only energy is exchanged during work interaction whereas both energy
and entropy are exchanged during heat transfer (Fig. 7–59). 2 Mass Flow
Mass contains entropy as well as energy, and the entropy and energy contents
of a system are proportional to the mass. (When the mass of a system is doubled, so are the entropy and energy contents of the system.) Both entropy and
energy are carried into or out of a system by streams of matter, and the rates
of entropy and energy transport into or out of a system are proportional to the
mass flow rate. Closed systems do not involve any mass flow and thus any entropy transfer by mass. When a mass in the amount of m enters or leaves a system, entropy in the amount of ms, where s is the specific entropy (entropy per
unit mass entering or leaving), accompanies it (Fig. 7–60). That is,
Entropy transfer by mass flow: Smass ms (7–74) Therefore, the entropy of a...
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- Spring '09