THERMOPHYSICAL PROPERTIES OF GASEOUS REFRIGERANTS FROM SPEED OF SOUND MEASUREMENTS .1. APPARATUS, MODEL, AND RESULTS FOR 1,1,1,2-TETRAFLUOROETHANE R134A

The speed of sound in gaseous 1,1,1,2-tetrafluoroethane (R134a) has been obtained between 233.16 and 340 K from measurements of the frequency of the radial acoustic resonances of a gas-filled spherical cavity. Perfect-gas heat capacities and second and third acoustic virial coefficients have been calculated from the results. The acoustic virial coefficients are used to estimate the density virial coefficients B(T) and C(T) and an effective square-well potential. The estimates of B(T) are consistent with B(T) deduced from high-quality equation-of-state measurements; those for C(T) are slightly inconsistent. The apparatus and its calibration with argon are described. © 1990 American Institute of Physics.