#### Turbines and Compressors: Screencasts

Explains the steps to determine work and outlet conditions for an irreversible steam turbine.

We suggest you list the important points in this screencast as a way to increase retention.

Performs an energy balance around a turbine accounting for flow work and shows how flow work can be lumped into the enthalpy term.

We suggest you list the important points in this screencast as a way to increase retention.

Optional screencast: Adiabatic Compression/Expansion: Enthalpy-Entropy Diagram

##### Important Equations:

For an ideal gas in an adiabatic reversible turbine or compressor:

$\frac{T_2}{T_1} = \left(\frac{P_2}{P_1}\right)^{\frac{R}{C_P}}$

where $$T_1$$ and $$P_1$$ are the inlet temperature and pressure and $$T_2$$ and $$P_2$$ are the outlet temperature and pressure. Absolute temperature must be used in this equation. $$R$$ is the ideal gas constant and $$C_P$$ is the constant-pressure heat capacity, which must be independent of temperature to use this equation.

Turbine efficiency:

$\eta = \frac{W_{irreversible}}{W_{reversible}}$

For an adiabatic turbine or compressor:

$S_1 = S_2$

(i.e., inlet entropy = outlet entropy) This equation is used to determine outlet conditions for a reversible turbine if the feed is not an ideal gas.

Compressible efficiency:

$\eta = \frac{W_{reversible}}{W_{irreversible}}$