On the behavior of the volume viscosity of atom-molecule mixtures

The evaluation of volume viscosity of dilute gas mixtures was analyzed using solution of a symmetric constrained singular linear system. The value of the volume viscosity of an atom-molecule mixture was highly sensitive to the value of a internal-energy relaxation cross section. The volume viscosity became discontinuous at the pure-atom limit when the cross section was approximated by zero. It was found that the volume viscosity approximation was 5%-10% for the mixtures relevant to combustion applications.