Throttling and Turbine Processes — Lesson 4

This lesson covers the concepts of throttling and turbine processes in thermodynamics. It delves into the specifics of refrigerant 134a being throttled at different pressures and temperatures, and the assumptions made during this process. The lesson also explains how to determine the specific reversible work and exergy destroyed during the throttling process. Furthermore, it discusses the adiabatic turbine process involving steam, where the power output of the turbine and the reversible power output are calculated. The lesson concludes with the calculation of the second law efficiency.

Video Highlights

03:48 - Calculation of the specific rate of entropy generation and exergy destroyed
10:20 - Explanation of the irreversible nature of the throttling process
17:31 - Calculation of the reversible work and the second law efficiency
19:07 - Calculation of the work lost due to irreversibility

Key Takeaways

- Throttling is an adiabatic process, and if heat loss from the throttle valve is not given, it can be assumed to be adiabatic.
- The throttling process is an isenthalpic process, meaning the enthalpy remains constant.
- In a turbine process, the kinetic energy change must be included in the calculations.
- The second law efficiency of a process can be calculated as the actual work output divided by the reversible work output.