Elsevier

Fluid Phase Equilibria

Volume 414, 25 April 2016, Pages 60-64
Fluid Phase Equilibria

Surface tension and liquid viscosity measurement for binary mixtures of R134a with R1234yf and R1234ze(E)

https://doi.org/10.1016/j.fluid.2016.01.013Get rights and content

Abstract

The surface tension and liquid kinematic viscosity of two binary refrigerant mixtures 1,1,1,2-tetrafluoroethane (R134a) (1) +2,3,3,3-tetrafluoroprop-1-ene (R1234yf) (2) and R134a (1) + trans-1,3,3,3-tetrafluoroprop-1-ene (R1234ze(E)) (2) were measured in the temperature range from 293 K up to the liquid–vapor critical point with the surface light scattering (SLS) method. The experimental data were correlated as a function of temperature and mole fraction of the pure components. For surface tension, the average absolute deviations are 0.019 mN∙m−1 for R134a + R1234yf and R134a + R1234ze(E). For liquid viscosity, the average absolute deviations are 0.96% and 1.16% for R134a + R1234yf and R134a + R1234ze(E), respectively.

Introduction

Recently, 2,3,3,3-Tetrafluoroprop-1-ene (R1234yf, CF3CFdouble bondCH2,754-121-1), with zero ODP and low GWP (100 year GWP = 4) [1], has been proposed as a drop-in replacement for 1,1,1,2-tetrafluoroethane (R134a) [2], [3]. Trans-1, 3, 3,3-Tetrafluoroprop-1-ene (R1234ze(E), CHFdouble bondCHCF3, 29118-24-9) is also a promising candidate with low GWP (100-year GWP = 6) and could be mixed with other refrigerants. However, their main drawbacks, flammability and minor cooling capacity could hinder their application. In order to overcome these limitations related to R1234yf and R1234ze(E), the binary mixtures of R1234yf and R1234ze(E) with R134a have been developed [4]. Lee et al. [5] found R134a + R1234yf mixture with 10–11% R134a is virtually non-flammable and azeotropic. Its coefficient of performance (COP), capacity and discharge temperature are similar to those of R134a. R450A (42% R134a + 58% R1234ze(E) in mass fraction), with non-flammability, a zero ODP and a GWP of 547, was developed by Honeywell as a replacement of R134a. Additionally, R450A was listed in the Significant New Alternatives Policy (SNAP) program by America Environmental Protection Agency. Mota-Babiloni [6] carried out an experiment in a vapor compression plant and proved that R450A was a good candidate to replace R134a.

Thermophysical properties of the refrigerant are basic data and used for designing condenser and evaporator in a refrigerator. Raabe et al. [7] conducted an experiment on the vapor–liquid equilibrium (VLE) property of blend R134a + R1234ze(E) at a temperature range from 273 K to 330 K by molecular simulation method. Kamiaka et al. [8] performed the VLE properties of the binary mixture R134a + R1234yf at mass fractions of R1234yf from 25% to 80% over the temperature range from 273 K to 333 K. Chen et al. [9] measured the PVTx properties in the gas phase for binary mixture R134a + R1234yf in the range of temperature from 298.58 K to 403.24 K, pressure range from 567.5 to 3171.2 kPa. Surface tension and viscosity are two important thermophysical properties influencing the heat transfer, flow and phase change characteristic of the refrigerant. Unfortunately, there are no surface tension and viscosity data of mixture refrigerants R134a + R1234yf and R134a + R1234ze(E) in the literature.

In this paper, the surface tension and liquid kinematic viscosity of binary mixtures of R134a + R1234yf and R134a + R1234ze(E) were conducted by surface light scattering (SLS) method. The experimental surface tension and viscosity data were correlated as a function of temperature and mole fraction of the pure components.

Section snippets

Material

R134a was manufactured by Sinochem Modern Environmental Protection Chemicals (Xi'an) Co., Ltd., China with a declared mass purity of 0.999. R1234yf and R1234z were supplied by Honeywell with declared mass purity of 0.999. The complete specifications for the three refrigerants are given in Table 1.

In this work, the pure refrigerants were firstly purified by freeze-pump-thaw cycles, and then the mixtures were prepared by the following process. Firstly, a known quality of R1234yf or R1234ze(E)

Results

The surface tension and liquid kinematic viscosity of the mixtures of R134a (1) + R1234yf (2) at 3 mol fractions x1 of 0.3196, 0.6018 and 0.8070 were measured over the temperature range from 293 K to 363 K, and the experimental data were showed in Table 2. The surface tension and liquid kinematic viscosity of the mixtures of R134a (1) + R1234ze(E) (2) with x1 of 0.4446 were measured over the temperature range from 293 K to 369 K, and the experimental data were showed in Table 3. The saturated

Conclusions

In this work, the surface tension and liquid viscosity were measured for (R134a + R1234yf) and (R134a + R1234ze(E)) under saturated condition by surface light scattering (SLS). The experimental surface tension and viscosity data were correlated as a function of temperature and mole fraction of the pure components using the Redlich-Kister polynomial equation. For surface tension, the average absolute deviations are 0.019 mN∙m−1 for (R134a + R1234yf) and (R134a + R1234ze(E)). For liquid

Financial interest

The authors declare no competing financial interest.

Acknowledgments

This study was supported by the National Natural Science Foundation of China (Grant No. 51276142, 51476130) and the Specialized Research Fund for the Doctoral Program of Higher Education (20130201110046).

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