球共鸣声学法气体音速的测量原理及实验系统研究

本文阐述了通过音频信号共振频率测量气体音速的原理。同时还分析了实际的球共鸣器的结构对共振频率的影响并给予了相应的修正。据此设计和制作了一套高精度的球共鸣器和低频音频信号测量装置，建立了一套球共鸣声学法测量气体音速的实验系统。本文实验中研究温度、压力、气体音速测量的不准确度分别为±14mK、±2.0kPa和±0.0037％。通过对制冷剂R22饱和蒸气压和氩气低压下音速的测量验证了本实验系统的稳定性和精确性。

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 ±14mK,±2.0kPa 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.