A novel non-intrusive microcell for sound-speed measurements in liquids. Speed of sound and thermodynamic properties of 2-propanone at pressures up to 160 MPa

Abstract

A novel high-pressure, ultrasonic cell of extremely reduced internal dimensions (∼0.8 · 10 −6 m 3) and good precision for the determination of the speed of propagation of sound in liquids was conceived and built. It makes use of a non-intrusive methodology where the ultrasonic transducers are not in direct contact with the liquid sample under investigation. The new cell was used to carry out speed of sound measurements in 2-propanone (acetone) in broad ranges of temperature (265< T/K<340) and pressure (0.1< p/MPa<160). ( p, ρ, T) data for acetone were also determined but in a narrower T, p range (298 to 333 K; 0.1 to 60 MPa). In this interval, several thermodynamic properties were thus calculated, such as: isentropic ( κ s) and isothermal ( κ T) compressibility, isobaric thermal expansivity ( α p), isobaric ( c p) and isochoric ( c v) specific heat capacity, and the thermal pressure coefficient ( γ v). Comparisons with values found in the literature generally show good agreement.