Ultrasonic Absorption and Thermal Relaxation inCO2
作者:
M. C. Henderson,
J. Z. Klose,
期刊:
The Journal of the Acoustical Society of America
(AIP Available online 1959)
卷期:
Volume 31,
issue 1
页码: 29-33
ISSN:0001-4966
年代: 1959
DOI:10.1121/1.1907608
出版商: Acoustical Society of America
数据来源: AIP
摘要:
Measurements of ultrasonic absorption have been made in dryCO2, and inCO2with hydrogen admixtures, between 19°C and 146°C and at pressures from 0.1 to 650 atmos, and frequencies from 300 kc to 7 Mc. The absorption is described within experimental error by the relaxation formula throughout this range using either (a) a single relaxation time and a single relaxing specific heat representing the total of the vibrational modes, or (b) two relaxation times somewhat more than a factor of two apart, and two relaxing specific heats given by certain combinations of the component vibrations. The relaxation time, or times, varies inversely as the density throughout. The maximum absorption per wavelength comes at 32 kc/atmos at 25°C. Addition of hydrogen shifts theCO2relaxation time by 110 kc/percent by volume ofH2; this amount is in agreement with the shift determined by Knudsen and Fricke, provided their data is interpreted as being by volume and not by weight. The “classical absorption” at low pressures is 1.5 times the theoretical value.
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