THE FUNDAMENTALS OF ABSORBENCY OF FIBERS, TEXTILE STRUCTURES AND POLYMERS .1. THE RATE OF RISE OF A LIQUID IN GLASS-CAPILLARIES

The predicted rates of rise of water in glass capillaries of diameters 0.2 and 0.4 mm by a theory which includes the effect of inertia on th e movement of the liquid are in satisfactory agreement with experiment al data. With an immersion depth (dip length) in the liquid of about 3 mm at the commencement of wicking, the predicted effect of inertia on the rate of rise of liquid in the capillaries is negligible. For a di p length of about 1 mm there is a small inertial effect with the large r capillary which is indicated by a slightly more rapid initial rise o f the liquid relative to that when the dip length is about 3 mm. These results demonstrate that under the present test conditions the force of inertia is not an important factor in determining the rate of rise of liquid in the capillaries. The predicted initial volume rate of wic king of the liquid in the larger capillary is several times greater th an that of the smaller one. This result will have an important bearing on the design of fabrics with optimum wicking capabilities.