Experimental Investigation of Moisture Vapor Transmission through Tentage Fabrics.

摘要

In order to test the validity of a theoretical model of agent transfer through a fabric membrane and to develop a standardized method for testing infiltration through fabrics under steady wind and external conditions, an experimental apparatus and procedure have been developed using water vapor as a tracer. This experimental model is capable of measuring infiltration through a fabric membrane into a test cylinder under a variety of external wind speeds and internal overpressures. Experiments have been conducted on cotton duck, cotton oxford, and polyester duck. The data collected will be used to verify the results of the theoretical model and to compare the infiltration rates of different fabrics under a variety of conditions. A comparison of initial predictions made using the theoretical model with experimental results revealed that there was a slower rate of infiltration into the chamber in the experiments than was predicted by the theoretical model. It is thought that this difference is due to the fact that the computational code models the fabric an a membrane with constant properties, while in the experiment its properties are changing. For example, as the fabric absorbs moisture and the fibers swell, the permeability of the fabric is decreased.