Thermal conductivity of binary gas of thermal excitations with external scattering centres

The effective thermal conductivity of a quantum continious medium containing a two-component gas of thermal excitations and scattering centers is calculated. The results are valid at any relations between the interaction rates of thermal excitations with one another and with scattering centers. It is shown that, in addition to partial contribution, the coefficient of effective thermal conductivity also contains flow and diffusion terms associated with different physical mechanisms and with distinct physical meaning. The obtained general expressions are used for investigation of such systems of thermal excitations in crystals and quantum fluids as longitudinal and transverse phonons, phonons and magnons, phonons and rotons. The expressions obtained are compared with the results of other investigations and experiments.