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Meaning of thermal equilibrium for flowing steam Interpret the term 'thermal equilibrium' in the context of the flow state of steam in a process description. Choose the most appropriate characterization.

Difficulty: Easy

Isothermal
Isentropic
Hyperbolic
Polytropic

Correct Answer: Isothermal

Explanation:

Concept/Approach

Thermal equilibrium means no temperature gradients within the system; the temperature is uniform and does not change with time or position, which corresponds to an isothermal description.
Isentropic additionally requires reversibility (no entropy change), which is stronger than thermal equilibrium alone.

Final Answer
Isothermal

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