Model multiparameter distributions used in science and technology are analyzed and systematized. Particular attention is paid to the Rozin-Rammler-Weibull-Gnedenko and Kolmogorov-Gauss distributions, which adequately describe single and multiple crushing. The suitability of these distributions for modeling the granulometric composition of industrial waste from mechanical processing is confirmed by physical and computer experiments.

Keywords: distribution function, mathematical model, generalized hyperbolic distributions, crushing, bulk medium, mechanical processing

An original approach to describe airflow in the thin conic diffusor is suggested. It is based on approximate analytic solution of continuity equation. In addition simplified model of turbulence is combined. Reliability of derived formula is confirmed by comparison with finite-element solution for designed experimental setup. The elaboration is intended to direct computer simulation of multiphase flow.

Keywords: dust-air mixture, aspiration systems, turbulence, finite element modeling, separation diffuser, digital twin