Adiabatic steam turbine - find the second law efficiency

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SUMMARY

The discussion focuses on calculating the second law efficiency of an adiabatic steam turbine by determining both the actual and reversible work outputs. The reversible work output is derived from the condition that the entropy remains constant (s2 = s1), allowing for the calculation of vapor quality. The actual work output assumes the vapor quality (x) is 1, indicating that the steam exiting the turbine is saturated vapor, which contains no moisture. This definition of saturated vapor is crucial for understanding the efficiency calculations in thermodynamic processes.

PREREQUISITES
  • Understanding of thermodynamic principles, specifically the second law of thermodynamics.
  • Familiarity with steam properties and the concept of vapor quality.
  • Knowledge of adiabatic processes in thermodynamics.
  • Ability to perform calculations involving entropy and work output in steam turbines.
NEXT STEPS
  • Study the principles of thermodynamic cycles, focusing on the Rankine cycle.
  • Learn about the properties of saturated steam and how to use steam tables.
  • Explore the concept of entropy in thermodynamic systems.
  • Investigate methods for calculating turbine efficiency and performance metrics.
USEFUL FOR

Mechanical engineers, thermodynamics students, and professionals involved in power generation and steam turbine design will benefit from this discussion.

theBEAST
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Homework Statement


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The Attempt at a Solution


So pretty much for this question you want to find the actual work output of the turbine and the reversible work output.

To find the reversible (theoretical) work output, you know that s2 = s1, so based on that information you can find what the quality of the vapor coming out of the steam is and thus find the work output.

To find the actual work output, the solution suggests that the quality of the vapor coming out of the turbine is x = 1. This suggests that steam is coming out of the turbine. I don't understand why x = 1 for actual work output. Could someone please explain this?

Thanks
 
Physics news on Phys.org
The quality of saturated vapor is, by definition, 1. Saturated vapor has no moisture present.
 
SteamKing said:
The quality of saturated vapor is, by definition, 1. Saturated vapor has no moisture present.

So saturated steam and vapor mean the same thing then?
 

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