Comparison of the use of Washburn's equation in the distance-time and weight-time imbibition techniques

Two experimental methods are usually employed to study liquid penetration i n porous media. One of them is based on the measure of the height of the ad vance liquid front vs time, and the other one is based on the measure of th e weight gained by the porous system due to the liquid penetration vs time, Generally, the experimental data obtained from these techniques are analyz ed through Washburn's equation. However, depending on which of them is sele cted, different conditions, coming from the experimental method, are needed to be taken into account in order to get the correct application of Washbu rn's equation to the experimental data. Although these conditions are diffe rent for each method, we prove in this paper that only if these conditions are considered both techniques are equivalent to analyze imbibition experim ents using Washburn's equation, (C) 2001 Academic Press.