TY - JOUR

T1 - Transport properties of nonequilibrium gas flows

T2 - Models and applications

AU - Nagnibeda, Ekaterina A.

AU - Kustova, Elena V.

PY - 2005/3

Y1 - 2005/3

N2 - The aim of this report is the development of theoretical models of transport properties in real gas flows and the application of these models to the conditions near spacecraft and in high-enthalpy facilities. A survey of models of dissipative processes in different regimes is provided. The excitation of rotational and vibrational degrees of freedom and dissociation are taken into account, as well as effects of strong vibrational nonequilibrium and anharmonism of vibrations. The real gas effects on transport coefficients are examined in high-enthalpy conditions. Our method is based on the kinetic equations for distribution functions and different relations between relaxation times of processes under consideration. Heat conductivity, viscosity, diffusion and thermal diffusion coefficients of air species N2, O2, NO are calculated on the basis of the method developed in. Transport coefficients are calculated in a wide range of gas temperatures 200K < T < 12000.K, and at different values of the nonequilibrium factor Tv=T (Tv is the vibrational temperature), and varying degree of dissociation. A comparison with equilibrium transport coefficients and experimental data is carried out, and practical recommendations concerning the choice of the kinetic model are given. The real gas effects on transport coefficients are estimated. Polynomial approximations of transport coefficients are obtained, and the tables of the transport coefficients and polynomial coefficients are presented.

AB - The aim of this report is the development of theoretical models of transport properties in real gas flows and the application of these models to the conditions near spacecraft and in high-enthalpy facilities. A survey of models of dissipative processes in different regimes is provided. The excitation of rotational and vibrational degrees of freedom and dissociation are taken into account, as well as effects of strong vibrational nonequilibrium and anharmonism of vibrations. The real gas effects on transport coefficients are examined in high-enthalpy conditions. Our method is based on the kinetic equations for distribution functions and different relations between relaxation times of processes under consideration. Heat conductivity, viscosity, diffusion and thermal diffusion coefficients of air species N2, O2, NO are calculated on the basis of the method developed in. Transport coefficients are calculated in a wide range of gas temperatures 200K < T < 12000.K, and at different values of the nonequilibrium factor Tv=T (Tv is the vibrational temperature), and varying degree of dissociation. A comparison with equilibrium transport coefficients and experimental data is carried out, and practical recommendations concerning the choice of the kinetic model are given. The real gas effects on transport coefficients are estimated. Polynomial approximations of transport coefficients are obtained, and the tables of the transport coefficients and polynomial coefficients are presented.

UR - http://www.scopus.com/inward/record.url?scp=22344438357&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:22344438357

JO - European Space Agency (Scientific and Technical Reports) ESA STR

JF - European Space Agency (Scientific and Technical Reports) ESA STR

SN - 0379-4067

IS - 248

ER -