Flow with heat transfer at temperature

Consider next the case where heat [GrevIx = Jx Grev is rejected (i.e. transferred from the control volume CV at temperature 7) in a reversible steady-flow process between states X and Y, in the presence of an environment at Tq- [CrevIx is taken as positive. 

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 

The maximum (reversible) work obtained from the inner control volume CV is therefore equal to 

For a real (irreversible) flow process through the control volume CV between fluid states X and Y (Fig. 2.4), with the same heat rejected at temperature T [Q x = [0rev]x) the work output is [WcvJx. Heat [Qq x Iso be transferred from CV directly to the environment at Tq. From the steady-flow energy equation, 

The entropy flux from the control volume associated with the heat transfer is 

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