Experimental study of the speed-of-sound in gases with a spherical resonator

In this paper, the theory that speed-of-sound of gases was deduced from measurement of the frequencies of acoustic resonance had been revealed. The impact of resonance frequencies caused by the structure of the spherical resonator had been also discussed , and they were corrected by perturbation terms. A set of spherical resonator and acoustic signal measurement apparatus had been thus designed and manufactured with high precision, the experimental system of the speed-of-sound in gases with a spherical resonator had been established. In this study, the experimental uncertainties in temperature, pressure and speed-of-sound measurements are estimated to be ±14 mK, ±2.0 kPa and ±0.0037%, respectively. The stability and precision of the experimental system have been verified through the measurements of vapor pressure of refrigerant R22 and speed-of-sound in Ar.