Programming And Modelling Environment For Studies Of Gas Flows In Micro- And Nanostructures Based On Solving The Boltzmann Equation

摘要

A set of programs has been developed for modelling gas flows in micro- and nanostructures. The programs are based on a method for solving the kinetic equation by a finite-difference technique on a fixed space-velocity grid. A projection method is used for calculating the Boltzmann collision integral which ensures that the conservation of mass, momentum, and energy is rigorously satisfied and that the collision integral goes to zero under thermodynamic equilibrium conditions. An explicit flux conservative scheme is used for approximating the differential part. The solution of the resulting system of difference equations is found by splitting into stages of collisional relaxation and free molecular flow. The computational algorithm is realized on a multiprocessor system using MPI technology. A graphical shell has been developed for visualizing the results during the computations and for convenient variation of the physical parameters of the flow under study. Some calculations of flows through a periodic system of square holes and a periodic system of slots whose transverse dimension is on the order of the mean free path of the gas molecules, as well as some model calculations of a micropump design, are given as examples.