The fundamentals of absorbency of fibres, textile structures and polymers. I. 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 the movement of the liquid are in satisfactory agreement with experimental 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 dip length of about 1 mm there is a small inertial effect with the larger capillary which is indicated by a slightly more rapid initial rise of the liquid relative to that when the dip length is about 3 mm. Under the 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 wicking of the liquid in the larger capillary is several times greater than that of the smaller one. This result will have an important bearing on the design of fabrics with optimum wicking capabilities.