Chapman-Enskog theory presents accurate formulas for a multicomponent gas mixture under thermal

Thermodynamic equilibrium

In thermodynamics, a thermodynamic system is said to be in thermodynamic equilibrium when it is in thermal equilibrium, mechanical equilibrium, radiative equilibrium, and chemical equilibrium. The word equilibrium means a state of balance...

 and chemical equilibrium

Chemical equilibrium

In a chemical reaction, chemical equilibrium is the state in which the concentrations of the reactants and products have not yet changed with time. It occurs only in reversible reactions, and not in irreversible reactions. Usually, this state results when the forward reaction proceeds at the same...

. In elastic gases the deviation from the Maxwell–Boltzmann distribution in the equilibrium is small and it can be treated as a perturbation. This method was aimed to obtain transport equations

Generic scalar transport equation

The generic scalar transport equation is a general partial differential equation that describes transport phenomena such as heat transfer, mass transfer, fluid dynamics , etc. A general form of the equation is \big...

 more general than the Euler equations. It is named for Sydney Chapman and David Enskog

David Enskog

David Enskog was a Swedish mathematical physicist. Enskog helped develop the kinetic theory of gases by extending the Maxwell–Boltzmann equations.- Biography :...

.