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Measurement and correlation of high-pressure high-temperature hydrogen thermal conductivity


P. Woodfield1, S. Moroe2, K. Kimura2, M. Kohno2, J. Fukai2, Y. Takata2, K. Shinzato3 and M. Fujii3

1Griffith University, Australia
2Kyushu University, Japan
3AIST, Japan

Keywords: transient short hot wire
property: thermal conductivity
material: hydrogen

Measurements of the thermal conductivity of normal hydrogen gas in the range of temperatures from 323 K to 773 K and pressures from 0.3 MPa to 99 MPa are taken using a transient short hot wire method [1, 2]. A single platinum wire (diameter 9.9 micrometers) with a length of 11.32 mm is employed. The compact size makes it ideal for work at extremes of high pressure and temperature. The thermal conductivity is determined by comparing the measured volume-averaged temperature rise of the wire with the result of a high-precision numerical solution to the transient heat conduction equation. The finite-volume numerical solution is coded into a non-linear least-squares fitting procedure which automatically iterates the estimates of thermal conductivity and thermal diffusivity of the sample towards a converged minimum discrepancy between the calculated and measured transient temperature rise. The high-pressure apparatus and infrastructure is completely automated and is controlled remotely for safe handling of high-pressure hydrogen gas. Data is collected using a simple DC circuit with a synchronized two-channel 24 bit A/D converter operating at 50,000 s-1 and connected for direct four-terminal resistance measurement. The hot wire instrument is calibrated using low-density helium gas at 323 K. The thermal conductivity measurements are estimated to have an uncertainty of 1.7% (k=2). The new data shows a systematic deviation of 2% to 4% from an extrapolation of the low-temperature hydrogen thermal conductivity correlation developed by Roder [3]. By adapting Roder’s correlation, a new correlation of the thermal conductivity surface which represents the present measurements within 2% is developed. The correlation is applicable from 78K to 773 K and for pressures from 0 to 100 MPa. A survey of the thermal conductivity literature indicates that the present measurements extend the known thermal conductivity surface for normal hydrogen gas by an additional 30 MPa.

References
  1. M. Fujii et al., Int. J. Thermophys. 18, 327 (1997)

  2. P. L. Woodfield, et al., Int. J. Thermophys. 30, 1748 (2009)

  3. H. M. Roder, Int. J. Thermophys. 5, 323 (1984)

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