Continuum analytical modelling of thermal creep

A thermal creep process is studied in quite wide rectangular micro channels, sufficiently wide so that it is possible to consider this configuration as two parallel plates. The inlet and outlet reservoirs are maintained at the same constant pressure. A constant temperature gradient exists along the walls of the channel joining the two tanks. Thus a gas flow is induced and thermally sustained until steady conditions are reached. A complete analytical solution is derived in slip regime, yielding all the flow parameters, for Knudsen numbers smaller than 0.25. The analytical results are in good agreement with the numerical “exact” solution of the continuum equation system. Furthermore our continuum approach data are compared to those deduced from approaches based on Boltzmann equation model treatments: these various methods lead generally to a satisfactory agreement between their respective mean parameters. Nevertheless significant differences appear on the transversal velocity profiles and are further discussed.