The speed of sound in 3,3,3-trifluoropropene (R-1243zf) in the gaseous phase has been measured using a fixed-path cylindrical resonator. The experiment was conducted along nine quasi-isochoric lines in the temperature range of (313 to 363) K and pressure range of (170 to 983) kPa. The speed of sound at 92 state points (p,T) was obtained from accurate measurements of resonant frequencies of seven acoustic modes. The overall relative expanded uncertainty at the confidence level of 0.95 in the speed of sound measurements is estimated to be 1.8 × 10^–4. The ideal-gas heat capacity at constant pressure for R-1243zf was determined over the temperature range from the speed of sound measurement with a relative expanded uncertainty (k = 2) of less than 0.5%, and the second acoustic virial coefficient was also derived. The temperature dependence of the ideal-gas heat capacity at constant pressure was correlated with a polynomial approximation relationship. The measured speed of sound and the derived ideal-gas heat capacities and second acoustic virial coefficient were also compared with calculations of the available equation of state of 3,3,3-trifluoropropene.

中文翻译：

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用圆柱谐振器测量气相中3,3,3-三氟丙烯（R-1243zf）的实验声速

气相中3,3,3-三氟丙烯（R-1243zf）中的声速已使用固定路径圆柱谐振器进行了测量。沿着9条准等速线在（313至363）K的温度范围和（170至983）kPa的压力范围内进行了实验。通过准确测量七个声学模式的共振频率，可以获得92个状态点（p，T）处的声速。声音测量速度的置信度为0.95时，整体相对扩展不确定性估计为1.8×10 ^–4。R-1243zf在恒定压力下的理想气体热容量是根据声音测量的速度在一定温度范围内确定的，并具有相对扩展的不确定性（k= 2）小于0.5％，并且还得出了第二声维里系数。恒定压力下理想气体热容的温度依赖性与多项式近似关系相关。还将测得的声速，导出的理想气体热容量和第二声维里系数与可用的3,3,3-三氟丙烯状态方程的计算进行了比较。