3. Silo calculation and sizing

Sizing a storage silo involves defining the half-angle of the hopper inclination and the diameter of the outlet opening. In terms of flow, three effects are sought:

• generate a regular mass flow;

• prevent the formation of vaults;

• ensure controlled solid flow.

For a given powder under known storage conditions, the first point depends on the angle of inclination of the hopper, while the next two points depend on the size of the orifice.

The most widely used method for calculating silos is that proposed by Jenike. With regard to the flow regime, this method is based on a force balance performed on an infinitesimal element of solid in the hopper. This balance led Jenike to a model which, using the flow characteristics...