Efficient simulation of rarefied gas flows through tubes of finite length based on kinetic model equations

The flow of a rarefied gas through tubes of circular cross-section and finite length, driven by arbitrarily large gradients of pressure is simulated in a computationally efficient manner based on kinetic model equations. The governing Ellipsoidal model kinetic equation is discretized in the phase space by a finite difference scheme and the discrete velocity method. It is seen that good agreement is obtained with corresponding DSMC results in the literature. Due to the five-dimensional nature of the problem, various techniques have been used to reduce the computational effort. Convergence has been accelerated for small Knudsen flows using the Wynn-epsilon algorithm while memory usage optimization, grid refinement and parallelization have been introduced. Overall, a highly efficient deterministic algorithm has been developed. © 2011 American Institute of Physics