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Title: Measurement of the thermal conductivity of gases using a periodic line-source flow method
Author: O'Hair, John Gordon
ISNI:       0000 0001 3452 9912
Awarding Body: University of Surrey
Current Institution: University of Surrey
Date of Award: 1974
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Reliable and accurate values of the thermal conductivity of gases and gas mixtures are much needed by engineers and theoreticians, this being particularly true for high temperature gases. However, such values are difficult to obtain because of the problems of eliminating, or accurately accounting for, heat transfer through the apparatus by mechanisms other than conduction through the gas. In some cases there are significantly large discrepancies between experimental values of thermal conductivity and values which have been calculated using theoretical equations in conjunction with experimental values of viscosity. Viscosity measurements are believed to be more reliable than thermal conductivity measurements, and the kinetic theory relating the two properties is not in doubt, so the reliabilty of methods of measuring thermal conductivity is questionable. This thesis describes a technique for measuring thermal conductivity in which there are no corrections to be made for heat transfer by other mechanisms. The technique should, therefore, be free of the systematic errors which have proved most troublesome in many other methods. The technique involves the measurement of the temperature distribution downstream from a periodically varying line source of heat in a flowing gas. This information, along with knowledge of the velocity of the gas flow, enables the thermal diffusivity of the gas to be determined. The thermal conductivity can then be calculated if the density and specific heat of the gas at constant pressure are both known. The results of using this technique to measure the thermal conductivity of nitrogen, carbon dioxide and nitrogen-carbon dioxide mixtures are also given in the thesis. The results are compared with the correlated results of many other workers but no systematic discrepancies are apparent.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available