Abstract n-Pentane is one of the main components in many industrial fluids, and is widely used as the fuel. The speed of sound can be used for developing the Helmholtz energy formulation and calculating other thermodynamic properties, which has not been reported yet for supercritical n-pentane. In this paper, the speed of sound in supercritical n-pentane was measured by the Brillouin light scattering (BLS) technique within the temperature limits of (422.69–653.53) K along four isobars at p = (3.5, 6.0, 8.0, and 10.0) MPa. The relative uncertainty of our BLS experimental system is estimated to be less than 0.6% and the relative uncertainty of the reported speed of sound values is estimated to be 0.85% considering the influence of impurities in the sample. The dependences of the speed of sound on temperature and pressure were also analyzed. At the end, we compared the experimental data with the calculated values from the multiparameter EOS proposed by Span and Wagner and the Modified BWR EOS proposed by J. Ratanapisit and J.F. Ely. The AARD is 1.3% for the multiparameter EOS and 1.5% for the Modified BWR EOS, respectively.

中文翻译：

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在 (422.69–653.53) K 的温度和 (3.5–10.0) MPa 的压力下测量超临界正戊烷中的声速

摘要 正戊烷是许多工业流体的主要成分之一，被广泛用作燃料。声速可用于开发亥姆霍兹能量公式和计算其他热力学性质，这在超临界正戊烷方面尚未见报道。在本文中，超临界正戊烷中的声速是通过布里渊光散射 (BLS) 技术在 (422.69–653.53) K 的温度范围内沿 p = (3.5、6.0、8.0 和 10.0 处的四个等压线测量的) 兆帕。考虑到样品中杂质的影响，我们的 BLS 实验系统的相对不确定度估计小于 0.6%，报告的声速值的相对不确定度估计为 0.85%。还分析了声速对温度和压力的依赖性。最后，我们将实验数据与 Span 和 Wagner 提出的多参数 EOS 以及 J. Ratanapisit 和 JF Ely 提出的 Modified BWR EOS 的计算值进行了比较。多参数 EOS 的 AARD 分别为 1.3% 和修改 BWR EOS 的 1.5%。