Friction Factor and Reynolds Number in Porous Media Flow

The concept of hydraulic radius of pore space is used to substantiate that the square root of the permeability is the important length parameter in defining the friction factor and Reynolds number in flow through porous media. Hydraulic radius was defined by applying the Kozeny-Carman theory of hydraulic radius of pore space. It was found that various porous media had different relationships between friction factor and Reynolds number. Experimental results showed a similarity to the Moody diagram used for pipe flow, with a ratio of particle mean diameter to the mean hydraulic radius of pore spaces as the third parameter.