Thermal conductivities of argon, nitrogen and hydrogen between 300 and 400 K and up to 25 MPa

Abstract

The thermal conductivities of argon, nitrogen and hydrogen have been measured using an apparatus of the transient hot-wire type at three temperatures between 300 and 400 K and at a number of pressures up to 17 MPa for argon and 25 MPa for nitrogen and hydrogen. The results give accurate values for the low-pressure limit of the thermal conductivity and these are compared with theoretical estimates. For argon they are close to the values predicted by rigorous kinetic theory and for hydrogen close to the values predicted by the modified Eucken equation. For nitrogen the new experimental values are below those predicted by the Mason–Monchick equation and well below those predicted by the equation of Viehland, Mason and Sandler, which takes spin polarisation into account. The experimental results also show that the variation of thermal conductivity with density of a particular gas shows very little change with temperature over the range studied.