A novel method for characterization of liquid transport through micro-wicking arrays

Abstract

The existing methods for predicting/modeling the permeability of a wick structure involve the use of a capillary pressure model. Thus, the validity of the existing permeability models has not been verified independent of the capillary pressure. Here, for the first time, the permeability and capillary pressure of monoporous wick structures have been independently determined using a new experimental approach. In the new approach, the liquid mass flow rate against gravity is measured by testing the wick at its dryout threshold at different wicking lengths. The permeability and capillary pressure of the wick are then uniquely determined by curve fitting the wicking length-dependent mass flow data. The advantage of the developed method over Washburn’s rate of rise technique is that the current method yields both capillary pressure and permeability values while the former only returns the product of the two parameters. The permeability values obtained from the experiments were used to examine the accuracy of the existing permeability models.