Poiseuille flow in a capillary at all regimes of rarefied gas flows

Functional structure of relations between the Poiseuille gas flow rate through the capillaries and rarefaction parameter (Knudsen number), the gas/surface interaction parameter (accommodation coefficient) and cross-sectional shape of the capillaries is established. For this purpose, the numerical solutions of the relaxation kinetic equation and the Boltzmann equation with specular-diffuse boundary condition for the interaction of gas molecules with the inner surface of the capillary are used. Asymptotic expansion of the gas flow rate depending on the Knudsen number at small value of it is used also.