Rarefied gas flow in a circular pipe of finite length

The paper is devoted to the study of a rarefied gas flow through a circular pipe caused by small pressure differences between the reservoirs attached to the ends of the pipe. The analysis is based on of the direct numerical solution of the Boltzmann kinetic equation with the linearized model collision integral of Shakhov. The solution of the problem is computed for a wide range of the rarefaction parameter values and is compared with the kinetic and continuum solutions for an infinitely long circular pipe as well as with the flow into vacuum.

► Rarefied gas flow through a finite-length circular pipe is studied. ► The flow is caused by a small pressure drop. ► The problem is solved for a broad range of Knudsen numbers and pipe lengths. ► Results are obtained by solving numerically the linearized S-model kinetic equation. ► Comparisons with the asymptotic kinetic and Navier–Stokes solutions are presented.