# Joule-Thomson effect

The **Joule-Thomson effect** is also known as the *Joule-Kelvin effect*. This effect is present in non ideal gasses, where a change in temperature occurs upon expansion.

## Joule-Thomson coefficient[edit]

The Joule-Thomson coefficient is given by

where *T* is the temperature, *p* is the pressure and *H* is the enthalpy.

In terms of heat capacities one has

and

In terms of the second virial coefficient at zero pressure one has

## Inversion temperature[edit]

^{[1]}
^{[2]}

## References[edit]

- ↑ Jacques-Olivier Goussard and Bernard Roulet "Free expansion for real gases", American Journal of Physics
**61**pp. 845-848 (1993) - ↑ E. Albarran-Zavala, B. A. Espinoza-Elizarraraz, F. Angulo-Brown "Joule Inversion Temperatures for Some Simple Real Gases", The Open Thermodynamics Journal
**3**pp. 17-22 (2009)

**Related reading**