Theoretical and experimental investigation of heat conduction for large temperature differences at arbitrary Knudsen number

The plane steady-state heat conduction in monatomic gases at large temperature differences was studied. An approximate solution of the Boltzman equation, based on a two-sided Maxwellian velocity distribution function and the model of Maxwellian molecules, was investigated. This solution, obtained by using Maxwell's moment method, can be used to determine macroscopic quantities of state for arbitrary Knudsen numbers. A plane heat conduction cell was used to check this theory experimentally. Temperature and pressure dependent heat transfer measurements for temperature differences up to 300 K were performed. It is shown that the four-moment solution corresponds well to the experimental data in the whole region from the continuum to the free molecular limit.