Viscosity measurements of ammonia, R32, and R134a. Vapor buoyancy and radial acceleration in capillary viscometers

Journal Article · Mon Mar 01 00:00:00 UTC 1999 · International Journal of Thermophysics

DOI:https://doi.org/10.1023/A:1022644718603· OSTI ID:696843

Laesecke, A; Lueddecke, T O.D.; Hafer, R F; Morris, D J ^[1]

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1. National Inst. of Standards and Technology, Boulder, CO (United States). Physical and Chemical Properties Div.

The saturated liquid viscosity of ammonia (NH{sub 3}) and of the hydrofluorocarbons, difluoromethane (CH{sub 2}F{sub 2}, R32) and 1,1,1,2-tetrafluoroethane (CF{sub 3}-CH{sub 2}F, R134a), was measured in a sealed gravitational viscometer with a straight vertical capillary. The combined temperature range was from 250 to 350 K. The estimated uncertainty of the ammonia measurements if {+-}3.3 and {+-}2 to 24% for the hydrofluorocarbons with a coverage factor of two. The results are compared with literature data which have been measured with capillary viscometers of different design. Agreement within the combined experimental uncertainty is achieved when some of the literature data sets are corrected for the vapor buoyancy effect and when a revised radial acceleration correction is applies to data which were obtained in viscometers with coiled capillaries. An improved correction for the radial acceleration is proposed. It is necessary to extend international viscometry standards to sealed gravitational capillary instruments because the apparent inconsistencies between refrigerant viscosity data from different laboratories cannot be explained by contaminated samples.

• Sponsoring Organization: USDOE, Washington, DC (United States)
• OSTI ID: 696843
• Journal Information: International Journal of Thermophysics, Journal Name: International Journal of Thermophysics Journal Issue: 2 Vol. 20; ISSN 0195-928X; ISSN IJTHDY
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
AMMONIA
COMPARATIVE EVALUATIONS
DATA COVARIANCES
FLUORINATED ALIPHATIC HYDROCARBONS
MATERIAL SUBSTITUTION
REFRIGERANTS
TEMPERATURE RANGE 0273-0400 K
VISCOSIMETERS
VISCOSITY