Absolute Steady-State Thermal Conductivity Measurements by Use of a Transient Hot-Wire System

Published

March 1, 2000

Author(s)

H M. Roder, Richard A. Perkins, Arno D. Laesecke, Carlos A. Nieto de Castro

Abstract

A transient hot-wire apparatus was used to measure the thermal conductivity of argon with both steady-state and transient methods. The effects of wire diameter, eccentricity of the wire in the cavity, axial conduction, and natural convection were accounted for in the analysis of the steady-state measurements. Based on measurements on argon, the relative uncertainty at the 95% level of confidence of the new steady-state measurements is 2% at low densities. Using the same hot wires, the relative uncertainty of the transient measurements is 1% at the 95% level of confidence. This is the first report of thermal conductivity measurements made by two different methods in the same apparatus. The steady-state method is shown to complement normal transient measurements made by two different methods in the same apparatus. The steady-state method is shown to complement normal transient measurements at low densities, particularly for fluids where the thermophysical properties at low densities are not known with high accuracy.

Citation

Journal of Research (NIST JRES) -

Volume

105 No. 2

NIST Pub Series

Journal of Research (NIST JRES)

Pub Type

NIST Pubs

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Keywords

argon, convection, dilute gas, hot wire instrument, steady state, thermal conductivity, transient

Citation

Roder, H. , Perkins, R. , Laesecke, A. and Nieto de Castro, C. (2000), Absolute Steady-State Thermal Conductivity Measurements by Use of a Transient Hot-Wire System, Journal of Research (NIST JRES), National Institute of Standards and Technology, Gaithersburg, MD, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=831639 (Accessed April 23, 2024)