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Unformatted text preview: te of change
of entropy ·
Sgen 0 Substituting, the rate of entropy generation is determined to be ·
m 3s3 ·
m 1s1 (322.7 ·
m 2s2 0.18172 ·
300 0.03607 22.7 1.7405) Btu/min · R 180 Btu/min
8.65 Btu/min · R
Discussion Note that entropy is generated during this process at a rate of
8.65 Btu/min · R. This entropy generation is caused by the mixing of two fluid
streams (an irreversible process) and the heat transfer between the mixing
chamber and the surroundings through a finite temperature difference (another
irreversible process). EXAMPLE 7–21 Entropy Generation Associated with Heat Transfer A frictionless piston-cylinder device contains a saturated liquid–vapor mixture
of water at 100°C. During a constant-pressure process, 600 kJ of heat is transferred to the surrounding air at 25°C. As a result, part of the water vapor contained in the cylinder condenses. Determine (a) the entropy change of the water
and (b) the total entropy generation during this heat transfer process. SOLUTION We first t...
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This document was uploaded on 11/28/2012.
- Spring '09