This title examines the problems involved in modelling turbulent gas flows carrying a dispersed impurity in the form of solid particles. Particular attention is directed to the consideration of various collisional processes (particle particle, particle wall, particle body) occurring in heterogeneous flows. With the use of a large file of experimental and numerical data, dimensionless criteria responsible for the presence and intensity of the indicated interactions are suggested and verified. The characteristics of turbulent heterogeneous flows in channels (pipes), as well as near streamlined...