High speed effusion flows from a rectangular exit into a vacuum

This paper presents a set of analytical gaskinetic solutions of highly rarefied free molecular jet expanding into a vacuum from a rectangular exit. Different from the past work, these solutions are exact and they include completely three-dimensional flowfield properties of density, velocity components, temperature, and pressure. These results provide us the free molecular limiting results, opposite to the continuum flow situation. The evaluation speed is faster than particle simulation methods. They expect to find many possible applications, such as materials processing inside vacuum chambers, space and micro-propulsion devices, and molecular beams.

► Obtained exact solutions for high speed, collisionless, steady, rectangular jet. ► Compact solutions contains factors of exit speed ratio, and exit height and width. ► Solutions are applicable in materials processing in vacuum chamber, molecule beams. ► Computation speed is fast and solutions are validated with Monte Carlo simulations.