A New Speed-of-Sound Instrument Based on the Time-of-Flight Method and Measurements on R-1224yd(Z), R-1233zd(E), and R-1336mzz(E)

Abstract

A new apparatus for the measurement of speed of sound was developed using time-of-flight method. Using this method, the speed of sound is evaluated by measuring the propagation time of an ultrasonic signal between two transducers separated by a known distance. The acoustic cell design and a general description of the setup are presented. Calibration of the path length was performed over a temperature range of 278.15 K to 343.15 K against R-1336mzz(Z), which was selected as a calibration fluid since its equation of state (EoS) was developed based on highly reliable speed-of-sound data. Furthermore, saturation pressure measurements of R-1234yf were performed and compared with its EoS and previously reported experimental data for validation. The setup was then used to evaluate the speed of sound of saturated liquid in R-1224yd(Z), R-1233zd(E), and R-1336mzz(E) providing accurate and reliable speed-of-sound data. Results were compared with the EoS for each of these refrigerants and with the available data in the literature. The experimental uncertainties of the speed of sound, temperature, and pressure were evaluated to be \(0.1\,\%\), 30 mK, and 1.0 kPa, respectively.