A new thermocouple technique for the precise measurement of in-plane capillary water flow within fabrics

Abstract

A new method was proposed for the measurement of in-plane capillary water flow within fabrics automatically. The method was based on the use of thermocouples to measure temperature changes as the fabric absorbed water. The wicking length of three different woven fabrics and two knitted fabrics in the warp, weft and 45° bias directions was measured using this technique. The wicking length was found to have a linear relationship with the square root of time, in agreement with the Washburn equation. Comparing the results with the data acquired using the horizontal Byreck method, the thermocouple technique was found to be suitable for the precise measurement of in-plane capillary water flow through fabrics automatically. Moreover, based on this method, the feasibility of estimating the water contents of fabrics from temperature differences generated during the flow process was also investigated. We found that it was possible to estimate the water content of a fabric, provided the moisture level is below the critical water content at equilibrium. This can be used to estimate the water content of fabric when it is worn.