Unformatted text preview: m since no mass crosses the system boundary during the process. We note
that the entropy change of the wall is zero during this process since the state
and thus the entropy of the wall do not change anywhere in the wall. Heat and
entropy are entering from one side of the wall, and leaving from the other side.
Assumptions 1 The process is steady, and thus the rate of heat transfer through
the wall is constant. 2 Heat transfer through the wall is onedimensional.
Analysis The rate form of the entropy balance for the wall simplifies to
·
·
Sin Sout
14243 ·
Sgen {
Rate of entropy
generation Rate of change
of entropy ·
·
Q
Q
T in
T out
1035 W 1035 W
293 K
278 K ·
Sgen 0 ·
Sgen 0 Therefore, the rate of entropy generation in the wall is ·
Sgen, wall 0.191 W/K Note that entropy transfer by heat at any location is Q /T at that location, and
the direction of entropy transfer is the same as the direction of heat transfer.
To determine the rate of total entropy generation during this heat transfer
process, we exte...
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This document was uploaded on 11/28/2012.
 Spring '09

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