Understanding Ideal Gas Mixture and Turbine Efficiency — Lesson 2

This lesson covers the concept of an ideal gas mixture and its application in an adiabatic turbine. It explains how to calculate the mass fraction of different gases in a mixture, the rate of change in availability, irreversibility, and the second law efficiency. The lesson also discusses the properties of the mixture, such as CP mix and R mix, and how to calculate them. It further delves into the concept of exergy and how it is affected when vapor is removed from a system. The lesson uses a detailed example of a turbine system to illustrate these concepts.

Video Highlights

03:44 - Explanation of the rate of change in availability
06:02 - Calculation of the actual work and irreversibility
09:01 - Explanation of the final state of the tank after vapor is taken out
13:14 - Calculation of the initial and final mass in the tank
21:54 - Calculation of the entropy balance to find the exergy

Key Takeaways

- The mass fraction of a gas mixture can be calculated using the molecular weights of the gases.
- The rate of change in availability, irreversibility, and second law efficiency can be determined using the properties of the gas mixture and the conditions of the system.
- The first law of thermodynamics can be applied to calculate the actual work done by an adiabatic turbine.
- The rate of exergy change can be calculated using the mass flow rate of the mixture and the change in enthalpy and entropy.
- The entropy balance can be used to determine the total entropy generated in a system.
- The exergy destroyed in a system can be calculated using the total entropy generated and the ambient temperature.