Dynamics of Dusty Gases

TLDR

This review focuses on the mechanics of dilute heterogeneous media, where particle–particle interactions are negligible, allowing shock wave, sound attenuation, and other flow‑field problems to be treated within a simplified dusty‑gas framework. The review aims to treat detailed transport processes between particles and gas independently of the full dynamics, concentrating on selected problems that yield significant results and illustrate useful analytical techniques. The authors introduce the governing equations and exchange processes, identify key physical parameters, and discuss selected problems to illustrate analytical techniques within the dusty‑gas framework. The review explicitly excludes problems involving particle–wall interactions and concentration separation in boundary layers or pipe flow.

Abstract

This review deals with a certain restricted portion of the mechanics of heterogeneous media. The volume fraction of the solid-particle or droplet cloud is considered to be so small that the interaction between individual particles may be neglected or highly simplified. This limitation applies to the individual flow fields about the particles as well as to collisions, and to heat and mass transfer as well as to momentum exchange between phases. Under this circumstance, the problem of detailed transport processes between particles and gas may be treated independently of the complete dynamical problem, and this aspect, being a study of its own, will be suppressed to a considerable extent here. There are problems, such as the impact of particles on walls, the concentration separation in boundary layers or pipe flow, in which the distortion of the particle flow field due to a solid wall or another particle is the central physical issue. These problems therefore lie outside the scope of the review. On the other hand, the structure of shock waves, sound attenuation, and many flow-field problems can be treated within our present restrictions. The basic equations and exchange processes will be introduced first, together with the physical parameters that indicate the relative importance of the particle cloud and the limitations of the dusty-gas concept. Then several different problems will be discussed that lead to some of the significant results in the field and illustrate analytical techniques that have proven useful.