The book is devoted to the problems of modeling turbulent gas fl ows carrying a dispersed impurity in the form of solid particles. Particular attention is directed to consideration of various collisional processes (particle-particle, particle-wall, particle-body) occurring in heterogeneous fl ows.With the use of a large fi le of experimental and numerical data, dimensionless criteria responsible for the presence and intensity of the indicated interactions have been suggested and verifi ed. The characteristics of turbulent heterogeneous fl ows in channels (pipes), as well as near streamlined bodies and in boundary layers are considered in detail. The results of physical and mathematical modeling of particle-laden gas fl ows obtained in the last few years by both Russian and foreign research workers are described and analyzed.The book is intended for research workers dealing with the study of the gas dynamics and heat and mass transfer of multiphase fl ows, as well as for teachers, post-graduates and students of universities.