High-Pressure Viscosity Measurements of 1,1,1,2-Tetrafluoroethane

Laesecke, Arno; Bair, Scott

doi:10.1007/s10765-011-0978-y

Cited by 31 publications

(16 citation statements)

References 33 publications

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“…97 The capability of this type of formulation was applied in several other reference correlations 24, 98–102 but it was shown that the singularity of the viscosity for V → V 0 leads to significant overpredictions even at modest extrapolations. 103 Therefore, free-volume terms were no longer considered in the present study.…”

Section: Formulation Conceptmentioning

confidence: 99%

Reference Correlation for the Viscosity of Carbon Dioxide

Laesecke

Muzny

2017

Journal of Physical and Chemical Reference Data

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119

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A comprehensive database of experimental and computed data for the viscosity of carbon dioxide (CO2) was compiled and a new reference correlation was developed. Literature results based on an ab initio potential energy surface were the foundation of the correlation of the viscosity in the limit of zero density in the temperature range from 100 K to 2000 K. Guided symbolic regression was employed to obtain a new functional form that extrapolates correctly to T → 0 K and to 10 000 K. Coordinated measurements at low density made it possible to implement the temperature dependence of the Rainwater-Friend theory in the linear-in-density viscosity term. The residual viscosity could be formulated with a scaling term ργ/T the significance of which was confirmed by symbolic regression. The final viscosity correlation covers temperatures from 100 K to 2000 K for gaseous CO2, and from 220 K to 700 K with pressures along the melting line up to 8000 MPa for compressed and supercritical liquid states. The data representation is more accurate than with the previous correlations, and the covered pressure and temperature range is significantly extended. The critical enhancement of the viscosity of CO2 is included in the new correlation.

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Section: Formulation Conceptmentioning

confidence: 99%

Reference Correlation for the Viscosity of Carbon Dioxide

Laesecke

Muzny

2017

Journal of Physical and Chemical Reference Data

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119

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“…The viscosity of the neat refrigerant was not measured as part of this work. A slightly different instrument with a very slow falling ‘cup’ sinker is needed . Refrigerant viscosity seldom is much greater than 2 mPa·s under the conditions investigated here.…”

Section: Refrigerant Viscositiesmentioning

confidence: 99%

“…Refrigerant viscosity seldom is much greater than 2 mPa·s under the conditions investigated here. The viscosity measurements at 40°C, 75°C and 100°C on R134a reported in the literature were used here.…”

Section: Refrigerant Viscositiesmentioning

confidence: 99%

The high‐pressure viscosity of refrigerant/oil systems

Bair

Baker²,

Pallister³

2017

Lubrication Science

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Application of the new quantitative elastohydrodynamics to the concentrated contacts operating within refrigerant compressors will require the accurate description of the viscosity of the lubricant that is diluted by the refrigerant. This article presents extensive viscosity measurements on polyolester and polyvinylether oils and their mixtures with low mass fractions (2–23%) of refrigerants R134a and R410a. Pressures up to 400 MPa and temperatures to 100°C were reached. Correlations are presented to predict the viscosity and pressure–viscosity coefficients at arbitrary temperatures and pressures and concentrations. Pressure–viscosity coefficients are compared with those derived from film thickness measurements using one of the popular definitions for the coefficient. Where comparisons can be made, the film‐derived pressure–viscosity coefficients were mostly inaccurate. Part of the problem has been the lack of a single well‐accepted and rigorous definition of the pressure–viscosity coefficient and the lack of an accurate film thickness formula that employs that definition. Copyright © 2017 John Wiley & Sons, Ltd.

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“…The viscosity of the refrigerant, R134a, which is 1,1,1,2-tetrafluoroethane, has been measured to pressures of 10 to 400 MPa in reference [17]. These data for 40, 75 and 100°C are shown in Figure 5 where the curves are a correlation fitted to the data.…”

Section: Refrigerantmentioning

confidence: 99%

A New High-Pressure Viscometer for Oil/Refrigerant Solutions and Preliminary Results

Bair

2016

Tribology Transactions

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The reliability and efficiency of refrigeration compressors is dependent on the lubricating effectiveness of the refrigeration oil which is necessarily a solution of oil and refrigerant. In this article, the development of a high pressure viscometer, which can operate at elastohydrodynamic lubrication (EHL) inlet pressures for oil/refrigerant solutions, is explained in detail. New viscosity measurements are presented for two compressor oils to 1.2 GPa. Preliminary results are given for a polyol ester with two concentrations of R134a refrigerant to 0.35 GPa. These are the first measurements of oil/refrigerant solutions to such high pressure. Temperature-pressureviscosity correlations are applied to all materials for use in modeling. Correlations are provided for the temperature and pressure dependences of the viscosity of the oils, the refrigerant and for the mixtures. The definition of -pressure-viscosity coefficient‖ is a pressing problem for elastohydrodynamics.

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High-Pressure Viscosity Measurements of 1,1,1,2-Tetrafluoroethane

Cited by 31 publications

References 33 publications

Reference Correlation for the Viscosity of Carbon Dioxide

Reference Correlation for the Viscosity of Carbon Dioxide

The high‐pressure viscosity of refrigerant/oil systems

A New High-Pressure Viscometer for Oil/Refrigerant Solutions and Preliminary Results

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