# Ch 8 - Thermodynamics of Flow Processes

In this lesson, you will learn to write entropy balance equations for closed systems. Entropy generation is the key because entropy is not conserved!

In this lesson, we develop the entropy balance equation for open systems. We then simplify the equation for SISO, SS, internally reversible processes in which changes in Epot and Ekin are negligible. We apply the simplified entropy balance equation to polytropic processes to derive equations for the shaft work.

In this lesson, we introduce isentropic efficiency for turbines, compressors, pumps, and throttling devices. We show how these processes can be visualized with the help of TS and HS Diagrams. We also discuss and analyze multi-stage compression systems with intercoolers and show how the isothermal efficiency can be used to evaluate their performance.

In this lesson, we derive equations that allow us to determine the lost work for a process or series of processes, such as a cycle. We show the connection between lost work and total entropy generation. We also introduce the Thermodynamic or 2nd Law Efficiency.

- Entropy Balances on Closed Systems

- Entropy Balances on Open Systems

- Isentropic Efficiency

- Irreversibility and Lost Work

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