Internal quantity of state

An internal state variable is a state variable that depends both on the generalized coordinates of the external bodies and on the mean values ​​of the coordinates and on the velocities of the particles in the system.

Examples of internal state variables are the density and the energy of a system.

The internal variables of a thermodynamic system in equilibrium depend only on its external variables and on the temperature :

${\displaystyle y_{k}=f(x_{1},x_{2},...,x_{n},T)}$

The following applies:

y _k internal quantity of state

x _{1 ... n} external state variables

T temperature

Individual evidence

1. ↑ Axel Schönbucher Thermal Process Engineering: Fundamentals and calculation methods for equipment and processes 1st edition. Springer Verlag, 2002, ISBN 978-3-540-42005-7