BIBLIOS

Document type
Journal articles

Document subtype
Full paper

Title
The thermal conductivity and heat capacity of fluid nitrogen

Participants in the publication
R.A. Perkins (Author)
H.M. Roder (Author)
D.G. Friend (Author)
C.A. Nieto de Castro (Author)
Dep. Química e Bioquímica
CQE

Summary
This paper presents new absolute measurements of the thermal conductivity and the thermal diffusivity of nitrogen made with a transient hot wire instrument. The instrument measures the thermal conductivity with an uncertainty less than ±1% and the thermal diffusivity with an uncertainty of ±5% except at the fluid critical point. The data cover the region from 80 to 300K pressures to 70 MPa. The data consist of 8 supercritical isotherms, 3 vapor isotherms, and 4 liquid isotherms.\\n\\nA surface fit is developed for our nitrogen thermal conductivity data from 80 to 300 K at pressures to 70 MPa. The data are compared with a recent theory for the first density coefficient of thermal conductivity and a new mode-coupling theory for the thermal conductivity critical enhancement. These data illustrate that it is necessary to study a fluid over a wide range of temperatures and densities in order to characterize the thermal conductivity surface.\\n\\nIsobaric heat capacity results were determined from the simultaneously measured values of thermal conductivity and thermal diffusivity, using the density calculated from an equation of state. The heat capacities obtained by this technique are compared to the heat capacities predicted by a recent equation of state developed specifically for nitrogen.


Institution
FACULDADE DE CIÊNCIAS DA UNIVERSIDADE DE LISBOA

Where published
Physica A: Statistical Mechanics and its Applications

Publication Identifiers

Publisher
Elsevier BV



Document Identifiers
DOI - https://doi.org/10.1016/0378-4371(91)90368-m
URL - http://dx.doi.org/10.1016/0378-4371(91)90368-m

Keywords
nitrogen

Tags
nitrogen thermal conductivity thermal diffusivity transient hot wire instrument low temperature high pressure supercritical Correlation surface fit Heat capacity

Notes
This paper presents new absolute measurements of the thermal conductivity and the thermal diffusivity of nitrogen made with a transient hot wire instrument. The instrument measures the thermal conductivity with an uncertainty less than ±1% and the thermal diffusivity with an uncertainty of ±5% except at the fluid critical point. The data cover the region from 80 to 300K pressures to 70 MPa. The data consist of 8 supercritical isotherms, 3 vapor isotherms, and 4 liquid isotherms.

A surface fit is developed for our nitrogen thermal conductivity data from 80 to 300 K at pressures to 70 MPa. The data are compared with a recent theory for the first density coefficient of thermal conductivity and a new mode-coupling theory for the thermal conductivity critical enhancement. These data illustrate that it is necessary to study a fluid over a wide range of temperatures and densities in order to characterize the thermal conductivity surface.

Isobaric heat capacity results were determined from the simultaneously measured values of thermal conductivity and thermal diffusivity, using the density calculated from an equation of state. The heat capacities obtained by this technique are compared to the heat capacities predicted by a recent equation of state developed specifically for nitrogen.

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