{"title":"计算正辛烷热力学性质的基本状态方程","authors":"R. Beckmüller, R. Span, E. Lemmon, M. Thol","doi":"10.1063/5.0104661","DOIUrl":null,"url":null,"abstract":"An empirical equation of state in terms of the Helmholtz energy is presented for n-octane. It is valid from the triple-point temperature 216.37 K to 650 K with a maximum pressure of 1000 MPa and allows for the calculation of all thermodynamic properties in the vapor and liquid phase, in the supercritical region, and in equilibrium states. In the homogeneous liquid phase, the uncertainty in density is 0.03% at atmospheric pressure. For pressures up to 200 MPa and temperatures between 270 and 440 K, density is described with an uncertainty of 0.1%. Outside this region, the uncertainty in the liquid phase increases to 0.5%. Densities in the vapor phase are estimated to be accurate within 0.5%. The uncertainty in vapor pressure depends on the temperature range and varies from 0.02% to 0.4%. Speed of sound in the liquid phase at temperatures below 500 K is described with an uncertainty of 0.1% or less. The isobaric heat capacity in the liquid phase can be calculated with an uncertainty of 0.1% and in the gas phase with 0.2%. A reasonable physical behavior of the equation of state was ensured by the analysis of numerous thermodynamic properties.","PeriodicalId":16783,"journal":{"name":"Journal of Physical and Chemical Reference Data","volume":" ","pages":""},"PeriodicalIF":4.4000,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"4","resultStr":"{\"title\":\"A Fundamental Equation of State for the Calculation of Thermodynamic Properties of n-Octane\",\"authors\":\"R. Beckmüller, R. Span, E. Lemmon, M. Thol\",\"doi\":\"10.1063/5.0104661\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"An empirical equation of state in terms of the Helmholtz energy is presented for n-octane. It is valid from the triple-point temperature 216.37 K to 650 K with a maximum pressure of 1000 MPa and allows for the calculation of all thermodynamic properties in the vapor and liquid phase, in the supercritical region, and in equilibrium states. In the homogeneous liquid phase, the uncertainty in density is 0.03% at atmospheric pressure. For pressures up to 200 MPa and temperatures between 270 and 440 K, density is described with an uncertainty of 0.1%. Outside this region, the uncertainty in the liquid phase increases to 0.5%. Densities in the vapor phase are estimated to be accurate within 0.5%. The uncertainty in vapor pressure depends on the temperature range and varies from 0.02% to 0.4%. Speed of sound in the liquid phase at temperatures below 500 K is described with an uncertainty of 0.1% or less. The isobaric heat capacity in the liquid phase can be calculated with an uncertainty of 0.1% and in the gas phase with 0.2%. A reasonable physical behavior of the equation of state was ensured by the analysis of numerous thermodynamic properties.\",\"PeriodicalId\":16783,\"journal\":{\"name\":\"Journal of Physical and Chemical Reference Data\",\"volume\":\" \",\"pages\":\"\"},\"PeriodicalIF\":4.4000,\"publicationDate\":\"2022-12-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"4\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of Physical and Chemical Reference Data\",\"FirstCategoryId\":\"5\",\"ListUrlMain\":\"https://doi.org/10.1063/5.0104661\",\"RegionNum\":2,\"RegionCategory\":\"工程技术\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"CHEMISTRY, MULTIDISCIPLINARY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Physical and Chemical Reference Data","FirstCategoryId":"5","ListUrlMain":"https://doi.org/10.1063/5.0104661","RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"CHEMISTRY, MULTIDISCIPLINARY","Score":null,"Total":0}
A Fundamental Equation of State for the Calculation of Thermodynamic Properties of n-Octane
An empirical equation of state in terms of the Helmholtz energy is presented for n-octane. It is valid from the triple-point temperature 216.37 K to 650 K with a maximum pressure of 1000 MPa and allows for the calculation of all thermodynamic properties in the vapor and liquid phase, in the supercritical region, and in equilibrium states. In the homogeneous liquid phase, the uncertainty in density is 0.03% at atmospheric pressure. For pressures up to 200 MPa and temperatures between 270 and 440 K, density is described with an uncertainty of 0.1%. Outside this region, the uncertainty in the liquid phase increases to 0.5%. Densities in the vapor phase are estimated to be accurate within 0.5%. The uncertainty in vapor pressure depends on the temperature range and varies from 0.02% to 0.4%. Speed of sound in the liquid phase at temperatures below 500 K is described with an uncertainty of 0.1% or less. The isobaric heat capacity in the liquid phase can be calculated with an uncertainty of 0.1% and in the gas phase with 0.2%. A reasonable physical behavior of the equation of state was ensured by the analysis of numerous thermodynamic properties.
期刊介绍:
The Journal of Physical and Chemical Reference Data (JPCRD) is published by AIP Publishing for the U.S. Department of Commerce National Institute of Standards and Technology (NIST). The journal provides critically evaluated physical and chemical property data, fully documented as to the original sources and the criteria used for evaluation, preferably with uncertainty analysis. Critical reviews may also be included if they document a reference database, review the data situation in a field, review reference-quality measurement techniques, or review data evaluation methods.