Number: 2003-005-1-100
Title: Recommended values of the viscosity of
molten iron and aluminum
Task Group
Chairman: W.A. Wakeham
Members: Marc
Assael, Michael Banish,
Ivan Egry, Ken
Mills, Akira Nagashima,
Tony Overfelt, Peter
Quested, John Redgrove,
and Yuzuro Sato
Completion Date: 2006 - project completed
Objective:
The widely different data obtained for the viscosity of molten iron
and aluminum will be critically reviewed via an interlaboratory comparison
and recommended values will be proposed.
Description:
Wide ranges of values of viscosity of both molten iron and aluminum
are reported in the literature. The most widely used method is some
form of oscillating vessel. For the oscillating cup a number of analytical
techniques have been used to convert the measurements (logarithmic
decrement and time period) to viscosity.
The Roscoe equation (1958) was recommended as providing
the most accurate data for molten metals. Ferriss et al (2002) have
pointed out there is a missing numerator in one of the expansions
and a number of workers and standard texts have quoted "1/2"
but expansion shows it to be "3/2".
In a parallel development chemical engineers have adopted
a set of equations for oscillating cup viscometers by Kestin and Newell.
which have been rarely used for molten metals.
There are two challenges:
-
Agreement about the equations used to determine
the viscosity by the oscillating cup method. At present the modified
Roscoe equation by Ferriss and the Kestin and Newell appear to give
similar results with one laboratory's data.
-
The widely different data obtained for the viscosity
of aluminum and iron need to be critically reviewed and recommended
values suggested. This may result in the need for an interlaboratory
comparison.
The project should lead to a consistent, internationally
approved set of values for the viscosity of these two metals, as an
exemplar for the field.
- Roscoe, R (1958), Proc. Phys. Soc. 72,
576
- Ferriss, D H; Quested, P N; Chapman, L A; and Day, A P (2002) "The
Choice of Equations for the Measurement of Viscosity by the Oscillating
Cylinder Method". Presented at ECTP, London.
Kestin, J and Newell, GF (1957) ZAMP VIII, 433
Progress:
The available experimental data for the density and viscosity of liquid
aluminum and iron have been critically examined with the intention
of establishing a density and a viscosity standard. All experimental
data have been categorized into primary and secondary data according
to the quality of measurement specified by a series of criteria. The
proposed standard reference correlations for the density of the aluminum
and iron are characterized by standard deviations of 0.65 and 0.77%
at the 95% confidence level respectively.
June 2005 - The final manuscript has been approved
by ICTNS.
Feb 2006 - Report published in J Phys. Chem.
Ref. Data, Vol. 35, No. 1, pp. 285-300, 2006
> doi:10.1063/1.2149380
Project completed
Last update: 7 March 2006
<project announcement published
in Chem.
Int.
25(3), 2003>
Page last modified 7 March 2006.
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