A new apparatus for measurement of the critical p-ρ-T properties based on the variable-volume method. (April 2022)

• Record Type: Journal Article
• Authors: Yao, Xiaoyu; Dong, Xueqiang; Zhao, Yanxing; Shen, Jun; Gong, Maoqiong
• Is Part Of: International journal of refrigeration. Volume 136(2022)
• Page Start: 220
• Page End: 228
• Publication Date: 2022-04
• Subjects: Variable-volume method -- Critical p-ρ-T properties -- Metal-bellows volumeter -- Critical opalescence; Méthode du volume variable -- Propriétés p-ρ-T critiques -- Volumètre à soufflet métallique -- Opalescence critique; Refrigeration and refrigerating machinery -- Periodicals; 621.56
• DOI: 10.1016/j.ijrefrig.2022.01.011
• Languages: English
• ISSNs: 0140-7007

Abstract

Highlights: A new variable-volume method for measuring critical pρT properties was designed with a mental-bellows volumeter. The device can measure the critical pρT properties by filling the fluid only once. All the experimental pρT data compare well with the data in the open literature. Abstract: In the present study, a new variable-volume apparatus equipped with a metal-bellows volumeter is designed to measure the critical pressure-density-temperature ( p-ρ-T ) properties by charging the device only once. The expanded uncertainties of the temperature, pressure and density measurements are assessed to be less than 20 mK, 4.2 kPa, and 1.6% ( k = 2, 95%), respectively. Moreover, the combined expanded uncertainty of the respective critical quantities is lower than 0.084 K, 10.2 kPa, and 2.4% ( k = 2, 95%). The average relative absolute deviation (ARAD) between the experimental p-ρ-T data and those calculated by the Refprop for the nitrogen is evaluated to be 0.18%. The p-ρ-T data and the critical properties of the 1, 1, 1, 2-tetrafluoroethane and difluoromethane are measured by the apparatus for verification. All the critical p-ρ-T data agree well with the accessible experimental data from the literature. The ARAD is evaluated to be 0.67% and 0.28% for the density of 1, 1, 1, 2-tetrafluoroethane at the vapor and liquid phases, respectively.