Erratum: Rarefied gas mixtures with large species mass ratio: Outflow into vacuum [Phys. Fluids <b>34</b>, 057106 (2022)]

Rarefied gas dynamics and its applications to vacuum technology

Basic concepts of rarefied gas dynamics are given in a concise form. Some problems of rarefied gas flows are considered, namely, calculations of velocity slip and temperature jump coefficients, gas flow through a tube due to pressure and temperature gradients, and gas flow through a thin orifice. Results on the two last problems are given over the whole range of gas rarefaction. A methodology f...

Expansion of a Finite Mass of Gas into Vacuum

Collisionless Gas Expanding into Vacuum

H IGH-SPEED collisionless, or free-molecular, gas flows passing through small circular or annular holes are fundamental problems with many real applications such as neutral gas expansion out of electric propulsion (EP) devices. Usually, the cold plume flow out of an EP device is modeled by assuming freemolecular flows with a nonzero uniform average exit velocity U0. Even when the average bulk v...

Rarefied Background Flow in a Vacuum Chamber

Spacecraft propulsion systems, such as Hall thrusters, are designed and tested in large vacuum chambers. The pumping capacity of modern facilities makes it possible to maintain pressures as low as 3 10 4 10 Pa. In this study, several free molecular models are developed to analyze the background flow inside a vacuum chamber. These models lead to various sets of analytical results including veloc...

Unified Solver for Rarefied and Continuum Flows in Multi- Component Gas Mixtures

A Unified Flow Solver (UFS) has been developed for simulations of rarefied, transitional and continuum flows based on direct numerical solution of the Boltzmann equation coupled to kinetic schemes of gas dynamics. The UFS uses dynamically adaptive mesh and automatic domain decomposition into kinetic and continuum domains based on continuum breakdown criteria. This paper describes UFS extensions...