Page 39 - Advanced Gas Turbine Cycles

16 Advanced gas turbine cycles

where [eo]$ the heat transferred to the environment from the control volume. [Wcv]; is
is
less than [(Wcv)REv]i and [eo]; is greater than [(Qo)REv]$. The leaving entropy flux
associated with this outward heat transfer is [Qo]i/To, such that the increase in entropy
across the control volume is
Sy - Sx = AScR - [Qo];/To, (2.12)
where AScR is the entropy created within the control volume. The work lost due to this
internal irreversibility is, therefore

-
ICR = [(WCV)REVI~ [Wcvli = (Bx - BY) - (ffx - ffy - [QoG)
(2.13)

2.2.2. Flow with heat transfer at temperature T

Consider next the case where heat [eREv]: = JidQREV is rejected (Le. transferred
from the control volume CV at temperature T) in a reversible steady-flow process
between states X and Y, in the presence of an environment at TO. [QREv]$ is taken as
positive.
Fig. 2.3 shows such a fully reversible steady flow through the control volume CV. The
heat transferred [Q,,];, supplies a reversible heat engine, delivering external work
[( and rejecting heat [(Qo)REv]$ to the environment.
The total work output from the extended (dotted) control volume is (Bx - BY), if the
flow is again between states X and Y. But the work from the reversible external engine is

(2.14)

xj cv I heat engine)
, Internally reversible !
I process I

[(Qo)REJ;
Environment at (po, To)
Fig. 2.3. Reversible proress with heat msfer at temperature T (to Camot engine) (after Ref 15J).