Evaluation of glycerol intermolecular free lengths at different temperatures by a thermo-acoustic approach

H. Khelladi (1) , Frédéric Plantier (2) , Jean-Luc Daridon (2)

1 FEI - Faculté d'Electronique et d'Informatique
2 LFCR - Laboratoire des Fluides Complexes et leurs Réservoirs

The mean intermolecular free length in glycerol is estimated over a wide range of temperatures by making use of thermo-acoustical parameters followed by measurements of glycerol surface tension. To achieve this objective, the glycerol surface tension is measured by using video digital image processing techniques to extract the entire experimental drop profile with subsequent numerical procedures based upon the Laplace equation of capillarity. Glycerol surface tension measurements are extended from 10°C - 90°C with a step of 10°C. The developed model for the evaluation of the glycerol intermolecular free length requires the estimate of the glycerol internal pressure which is derived, in this study, from the Tait equation by exploiting the glycerol nonlinearity parameter and further glycerol properties already measured in a previous study. The experimental results show that the mean intermolecular free length increases, with rise in temperature, from a small value. Inversely, the internal pressure decreases by increasing temperature which describes perfectly the dispersion part of cohesion and reflects the molecular ordering of glycerol versus temperature.

Mots clés: density; glycerol; internal pressure; Nonlinearity parameter; surface tension; ultrasonic wave velocity

Domaines: Chimie-Physique [physics.chem-ph]

H. Khelladi, Frédéric Plantier, Jean-Luc Daridon. Evaluation of glycerol intermolecular free lengths at different temperatures by a thermo-acoustic approach. International Congress on Ultrasonics, ICU 2011, Sep 2011, Gdansk, Poland. pp.381-384, ⟨10.1063/1.3703209⟩. ⟨hal-00830649⟩