A Dual-Path Pulse-Echo Instrument for Liquid-Phase Speed of Sound and Measurements on p-Xylene and Four...

Area of Science:

• Physical Chemistry
• Thermodynamics
• Materials Science

Background:

• Accurate speed of sound data is critical for understanding fluid properties and developing thermodynamic models.
• Existing measurement techniques may have limitations in temperature range, pressure, or precision.
• Novel refrigerants require precise thermophysical property data for safe and efficient application.

Purpose of the Study:

• To develop and validate a novel instrument for measuring the speed of sound in liquids.
• To present new, high-quality speed of sound data for several halogenated-olefin refrigerants.
• To compare experimental data with existing literature and theoretical models.

Main Methods:

• Utilized a dual-path, pulse-echo technique with a unique transducer mounting and a 2.5:1 path-length ratio.
• Employed automated data-collection protocols for enhanced efficiency and accuracy.
• Calibrated the instrument using high-purity propane and validated performance with p-xylene data.

Main Results:

• Successfully measured the speed of sound in halogenated-olefin refrigerants 2,3,3,3-tetrafluoroprop-1-ene [R1234yf], trans-1,3,3,3-tetrafluoroprop-1-ene [R1234ze(E)], trans-1-chloro-3,3,3-trifluoroprop-1-ene [R1233zd(E)], and cis-1,1,1,4,4,4-hexafluorobut-2-ene [R1336mzz(Z)].
• Data were collected over a temperature range of 230 to 420 K and pressures up to 50 MPa.
• Achieved an average relative expanded uncertainty in speed of sound measurements between 0.035% and 0.088%.

Conclusions:

• The developed instrument is reliable for accurate speed of sound measurements in liquids across a wide temperature and pressure range.
• The new experimental data provide valuable benchmarks for validating thermodynamic models of these important refrigerants.
• This work contributes essential thermophysical property data for the advancement of refrigeration and chemical engineering applications.