(588d) Comparative Study Between Simultaneous Determinations of Dynamic Viscosity and Density of Ethanol  Using a Straight and Coil Capillary Viscometers at Temperatures Between (313-353) K and Pressures up to 30 Mpa

In this work, a comparative study between viscosity and density determinations of ethanol using two different capillaries viscometers (straight and coil) was performed. The main objective of this analysis is to determine the influence that have the length of the capillary tube and the existing centripetal force in the coil tube in the determination of liquid viscosities and densities of pure fluids. For this reason, ethanol was used as the test fluid, determining the deviation between the data obtained with both tubes and the international literature. Moreover, for both cases the experimental uncertainty was estimated. The results show that, for the operating conditions used, the coil capillary viscometer has the smallest deviation from literature data (for viscosity: 0.45% coil capillary and 0.6% straight capillary; for density: 0.04% coil capillary and 0.051% straight capillary). This can be explained because there is a long length difference between the two tubes (5.5 m and 0.76 m for coil and straight tube, respectively). In the estimation of relative combined expanded uncertainty, there is no noticeable difference between the two tubes (for viscosity: 0.72% and 0.73% for coil and straight capillary, respectively; for density: 0.07% and 0.071% for coil and straight capillary). It is noteworthy that the effect of centripetal force in the calculation of the uncertainty was evaluated to be ± 0.12%. All measurements were carried out at temperature up to 353 K and pressures up to 30 MPa