Storage and gravity flow of granular solids in silos Engineering and accidentology

This article reviews the state of the art concerning the gravity flow of granular solids in silos. It should be noted that the term "granular solids" is used here to designate materials with a large particle size, for which gravitational forces (weight) predominate over forces such as van der Waals forces, electrostatic forces, etc. (see detailed descriptions in [J 4 101] ). Generally speaking, cereal grains, granulates (polymers, catalysts, detergents, fertilizers, etc.), pharmaceutical tablets, gravel, etc. fall into this category.

In the article [J 2 258] , the basic principles and definitions, as well as the elementary mechanisms involved, were first introduced. Flow regimes, stress fields (static and dynamic) and velocity profiles were then detailed. For all these aspects, the available models and their reliability were discussed, along with the basic principles and assumptions on which they are based.

This article focuses on the practical aspects of silo engineering. Some basic concepts and important models (detailed in the article [J 2 258] ) are first presented. Discharge mass flow rate is undoubtedly one of the most sought-after parameters. The correlations used to evaluate this mass flow rate and the main influential parameters are described in detail. The importance of the residence time distribution (RSD) of granular solids in silos and the problem of segregation are then discussed. Finally, the accidentology and risks associated with silos are presented.