Difference between pearmeability and permeability coefficient?

Answer 1

Permeability is part of the proportionality constant in Darcy `s law which relates discharge (flow rate) and fluid physical properties (e.g. viscosity), to a pressure gradient applied to the porous media:

The proportionality constant specifically for the flow of water through a porous media is called the hydraulic conductivity; permeability is a portion of this, and is a property of the porous media only, not the fluid. Given the value of hydraulic conductivity for a subsurface system, k, the permeability can be calculated as:

• κ is the permeability, m2
• k is the hydraulic conductivity, m/s
• μ is the dynamic viscosity, kg/(m·s)
• ρ is the density of the fluid, kg/m3
• g is the acceleration due to gravity, m/s2.
• v is the superficial fluid flow velocity through the medium (i.e., the average velocity calculated as if the fluid were the only phase present in the porous medium)
• ΔP is the applied pressure difference (Pa)
• Δx is the thickness of the bed of the porous medium (m)

Answer 2

Permeability refers to the ability of a material to allow fluids to pass through it. Permeability coefficient, on the other hand, is a quantitative measure that represents the rate at which a fluid can flow through a unit area of a porous medium under a unit pressure gradient. In simple terms, permeability is a property of a material, while permeability coefficient is a quantitative measure of how easily a fluid can flow through that material.