L. Cusco et Jpm. Trusler, IDENTIFICATION OF ENVIRONMENTALLY ACCEPTABLE LOW-SOUND SPEED LIQUIDS, International journal of thermophysics, 16(3), 1995, pp. 675-685
Liquids with unusually low sound speeds are required as filling fluids
for sonar targets and acoustic lenses. In this paper, we report on th
e search for environmentally acceptable fluids for these purposes. A p
recision variable pathlength interferometer, incorporating some novel
features, has been constructed and used to make sound speed measuremen
ts on a number of liquids with low speeds of sound. The measurements w
ere made, with a precision of +/-0.05% and an uncertainty of +/-0.2%,
at atmospheric pressure and at various temperatures in the range 273.1
5 to 303.15 K. The most promising low-sound speed liquid identified wa
s n-perfluorohexane, which has a sound speed below 600 m . s(-1) in th
e temperature range of interest here. This liquid forms homogeneous mi
xtures over al least part of the temperature range with several alkane
s including n-pentane, n-hexane, and 2,2-dimethylbutane. Experimental
results for binary mixtures of perfluorohexane isomers with each of th
e aforementioned alkanes are reported.