The flow in a Supersonic Injection Feeder involves relatively thick boundary layers in a narrow channel. When the pressures at the extremities of such a duct are adjusted to produce a compression shock, the shock structure is radically different from a plane discontinuity. This difference arises solely due to shock wave-boundary layer interaction, and gives rise to the so-called "pseudo-shock". In this paper, results of CFD simulations of a pseudo-shock in clean gas (air) are compared with predictions of the "Diffusion" model, the "Modified-Fanno" model and with experimental results. An analysis of the effect of small particles on pseudo-shock structure is offered in the form of extensions of the analytical models and CFD simulations.