Measurement of the thermal conductivity of gases by the transient hot-wire method
The construction and operation of an apparatus to measure the thermal conductivity of gases and gas mixtures, by using the transient hot-wire technique, is described. The description is set in the context of the development of this method over the past 12 years in a number of centres and a bibliography of the results obtained in this period is given. The sources of error and the consequences both to the limitations to experimental conditions and to the corrections to be applied are discussed in detail. The experimental and theoretical procedures described are representative of the current state of this developing technique. Results are given for helium and correlating equations given for a data for other gases and gas mixtures. These indicate a precision of 0.1 % and an absolute accuracy of 0.5 % for the apparatus described for temperatures from 300 to 470 K and pressures from 1 to 25 MPa.