Phase and viscosity behaviour of refrigerant–lubricant mixtures (original) (raw)
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Journal of Chemical & Engineering Data, 2004
In this paper, an extensive experimental work has been carried out on phase-equilibrium measurements in binary systems constituted by refrigerants CF 3-CHF 2 (R125), CF 3-CH 2 F (R134a), CF 3-CH 3 (R143a), and CH 2 F 2 (R32) and a commercial perfluoropolyether Fomblin YLOX100 and Fluorolink D10H, used as lubricant oils. The measurements are related both to vapor-liquid and liquid-liquid equilibria, and the collected experimental data have been interpreted with the extended Flory-Huggins model. This model allows, simultaneously, good performances in the description of both the vapor-liquid isotherms and liquid-liquid miscibility gaps with the same set of adjustable parameters.
Towards the viscosity of refrigerant/oil mixtures
Fluid Phase Equilibria, 2003
The paper describes the current status of knowledge of the viscosity of refrigerants R32, R124, R125, R134a, R141b and R152a and their mixtures, in the liquid and vapour states along the saturation line and as a function of pressure. The analysis reveals that there remain significant discrepancies between the results of measurements of the viscosity of pure refrigerants by different authors. These differences are particularly marked when different techniques are employed but almost always exceed the claimed mutual uncertainties. The theoretically-based scheme of Vesovic and Wakeham (VW) for the prediction of the viscosity of mixtures from their pure components is used in a modified form to examine predictions of the behaviour of refrigerant mixtures.
Absorption of Refrigerant Mixtures in Lubricant Oil
A methodology is proposed to calculate the absorption of a binary refrigerant mixture in lubricant oil. The model is based on an apparent diffusion coefficient formulation that accounts for both molecular diffusion and macroscopic motion due to density instability in the liquid phase. Diffusion in the vapour and liquid phases are coupled with a thermodynamic model for interfacial equilibrium. Results are compared with experimental data available in the literature for absorption of R410a in a stagnant layer of Polyol-Ester Oil (POE68). The adequacy of the formulation will be assessed in light of the basic assumptions and performance of the model.
Modeling absorption of pure refrigerants and refrigerant mixtures in lubricant oil
International Journal of Refrigeration, 2006
This paper addresses the problem of absorption of refrigerant vapor in a stagnant layer of lubricant oil. The bulk motion of the solute is described in terms of apparent diffusion coefficients that encompass both molecular diffusion and possible macroscopic motion induced by liquid density instability and surface tension. In absorption of refrigerant mixtures, diffusion in the vapor and liquid phases are coupled with a thermodynamic model for interfacial equilibrium. Results are compared with experimental data available in the literature for absorption of several refrigerants in polyol ester oil (POE68). The adequacy of the formulation is assessed in the light of its basic assumptions and performance of the model.
An experimental investigation and modelling of the viscosity refrigerant/oil solutions
International Journal of Refrigeration, 2009
This paper presents experimental data for the viscosity of solutions of refrigerant R600a (isobutane) with mineral compressor oils Azmol, Reniso WF 15A, and R245fa (1,1,1,3,3pentafluoropropane) with polyolester compressor oil Planetelf ACD 100 FY on the saturation line. The experimental data were obtained for solution of R600a with mineral compressor oil Azmol in the temperature range from 294.7 to 338.1 K and the concentration range 0.04399 w R 0.3651, the solution of R600a with mineral compressor oil Reniso WF 15A at the temperatures from 285.8 to 348.4 K and the concentration range 0.03364 w R 0.2911, the solution of R245fa with polyolester compressor oil Planetelf ACD 100 FY at the temperatures from 309 to 348.2 and the concentration range 0.06390 w R 0.3845. The viscosity was measured using a rolling ball method. The method for prediction of the dynamic viscosity for refrigerant/oil solutions is reported.
Journal of Fluorine Chemistry, 2000
An extended Flory±Huggins model has been developed and used to interpret liquid±liquid phase diagrams related to binary mixtures of CFC±lubricating oil for which miscibility gaps of UCST, LCST and hourglass type are present. Some liquid±liquid equilibrium measurements have been carried out for the¯uorinated compounds R134a, R125, R143a, and R32 in mixtures with polyester-based lubricating oils (PES), pentaerythritol tetraheptanoate (PTE) and trimethylolpropane triheptanoate (TTE). The extended Flory±Huggins model has been applied in the simultaneous description of the liquid±liquid and vapor±liquid phase equilibrium using the same set of adjustable parameters. On the basis of the results obtained in ®tting binary systems, a predictive approach has been developed for the description of a miscibility gap related to a mixture formed by two or more halogenated compounds with a lubricating oil. #
International Journal of Refrigeration, 1985
able ~'2. However, a generalized design procedure would require temperature dependence of liquid viscosity coefficients. The most common one is the Andrade equation relating the natural logarithm of viscosity coefficient and the inverse temperature. This equation is not exact over the entire liquid range although it is a good approximation below the normal boiling point. Based on the theory of corresponding states, several empirical correlations have been proposed for monoatomic and diatomic liquefied Volume 8 Number
Measurement of Kinematic Viscosity of Refrigeration Oil and R1234yf Mixture
2021
Refrigerant dissolves in refrigeration oil which is used to lubricate the compressor. Because the viscosity of the oil in which the refrigerant is dissolved is significantly reduced, the rate of the reduction is important information to select a proper oil. However, viscosities have not been sufficiently measured for mixtures of refrigeration oil and new refrigerants which are HFOs and mixtures of HFO and HFC. In order to utilize HFO refrigerants in alternative refrigeration systems, viscosity data of mixtures of refrigeration oil and HFO are essential. In this study, mixture of a refrigeration oil and refrigerant (R410A and R1234yf) viscosity are measured with temperature from 40 to 80 ℃ (313 – 353 K) and the oil mass concentration from 80 to 100 % using the tandem capillary tubes method. In this method, the test fluid flows inside two different length and same diameter capillary tubes connected in series in order to eliminate the pressure drop at the inlet and outlet therefore the...