Surface tension effects in capillary viscometers: an evaluation with an experimental comparative analysis

摘要

Surface tension effects in capillary viscometry play an important role in the accuracy of the measurements of kinematic viscosity. An experimental evaluation of these effects has been carried out using capillary viscometers having the same shape and size of the upper and lower bulbs, the same timing bulb, the same capillary radius, but different capillary lengths. The measurement method applied for evaluating the correction factor and its associated uncertainty is described. As an example, results of the kinematic viscosity of the liquid n-nonane, obtained with two Ubbelohde viscometers, which have been calibrated with bi-distilled water, are presented.