Application a hybrid solver to gas flow through a slit at arbitrary pressure ratio

Abstract

A hybrid solver, dynamically coupling the direct numerical solution of the kinetic equation and hydrodynamic Navier–Stokes equations is applied for numerical investigation of the gas flow through a slit at pressure ratio of 0.1, 0.5 and 0.9, including flow into vacuum and Knudsen number from slip to transitional regime. The coupling is achieved by matching half fluxes at the interface of kinetic and Navier–Stokes sub-domains, which are decomposed based on the local Knudsen number and macroparameters gradients. The solver efficiency is increased via MPI (Message Passing Interface) parallelization. The improvement in accuracy over Navier–Stokes equations and the computational efficiency of the proposed solver are assessed via comparison with pure kinetic solution in terms of mass flow and local parameters. The capability of hybrid solver to apply for vacuum science problems is demonstrated.