Damköhler number

Damköhler number is the relation of reaction timescale to the convection time scale, the volumetric flow rate through the reactor for continuous (plug flow or stirred tank) or semi-batch chemical processes. Damköhler number can be defined as:

Capillary number

The capillary number represents the relative effect of viscous drag forces versus surface tension forces acting across an interface between a liquid and a gas, or between two immiscible liquids. It is represented as: