Vor kurzem ist der Fachartikel "Measurement procedure for acoustic absorption and bulk viscosity of liquids" in der international renommierten Fachzeitschrift "Measurement" erschienen. Leander Claes und die Koautoren der Universität Paderborn und der Technischen Universität Berlin präsentieren in diesem Beitrag ein Messverfahren zur Bestimmung der bisher noch kaum erforschten Volumenviskosität von Flüssigkeiten. Der Lösungsansatz basiert auf einer Messung der frequenzabhängigen akustischen Absorption durch Auswertung spektraler Eigenschaften von Ultraschallsignalen eines Puls-Echo-Messsystems. Außerdem wird darin ein Verfahren zur experimentellen und rechnerischen Kompensation systematischer Messabweichungen beschrieben.
Abstract:
Measurement procedure for acoustic absorption and bulk viscosity of liquids
A measurement procedure using a modified two-chamber pulse-echo experimental setup is presented, enabling acoustic absorption and bulk viscosity (volume viscosity) measurements in liquids up to high temperature and pressure. Acoustic absorption measurements are particularly challenging, since other dissipative effects, such as diffraction at the acoustic source and at acoustic reflectors, are typically superimposed to the measurement effect.
Acoustic field simulations are performed, allowing to investigate acoustic wave propagation qualitatively. The absorption coefficient is determined by evaluating the signal spectrum's raw moments and applying a method to identify and correct systematic measurement deviations. Measurement uncertainties are estimated by a Monte Carlo method. In order to validate the present measurement procedure, the acoustic absorption in liquid methanol, n-hexane, n-octane, and n-decane is determined experimentally and compared to literature data. The measurement results for methanol are additionally validated by comparison to bulk viscosity data sampled with molecular dynamics simulation.
DOI: 10.1016/j.measurement.2021.109919
