Kozeny–Carman equation

The Kozeny–Carman equation estimates permeability from porosity, specific surface area, and geometric factors. It models flow through porous materials using an idealized network of tortuous capillary passages.

Darcy's law: A relation linking fluid flow through a porous medium to pressure gradient, permeability, viscosity, and flow area. The equation supplies a pore-geometry estimate for the permeability used in Darcy’s law.
Pore space: The interconnected void volume within a porous material. Only accessible pore space contributes directly to through-flow and effective permeability.
Groundwater flow: The movement of water through saturated soil and rock. Hydrogeologists use permeability estimates to characterize aquifers and subsurface flow.
Carman–Kozeny constant: A dimensionless factor in the Kozeny–Carman relation that combines geometric and flow-path effects. Its value absorbs structural details that the equation does not represent explicitly.
Porosity: The fraction of a material’s bulk volume occupied by voids. The equation predicts higher permeability as connected pore volume generally increases.
Pore throat: A narrow connection between larger voids in a porous material. Throat constrictions can dominate flow resistance despite substantial total porosity.
Petroleum reservoir: A subsurface rock formation that stores and transmits producible hydrocarbons. Reservoir characterization applies the relation to connect rock texture with flow capacity.
Ergun equation: An empirical pressure-drop relation for fluid flow through packed beds, including viscous and inertial terms. It extends packed-bed pressure-drop prediction beyond the low-flow regime emphasized by Kozeny–Carman.
Specific surface area: The surface area of a material per unit mass or volume. The equation uses pore-wall area to represent the resistance encountered by flowing fluid.
Fluid viscosity: A fluid’s resistance to deformation and flow. The equation’s permeability estimate enters flow calculations alongside viscosity.

Linked from 4 pages