Numerical Validations for a Set of Collisionless Rocket Plume Solutions

This paper presents some validation results for a set of improved, complete, gaskinetic solutions for a rarefied jet expanding into vacuum. A classical rocket plume model with a cosine relation and direct simulation Monte Carlo results are used to validate this set of analytical solutions. For the analytical and direct simulation Monte Carlo results, there is excellent agreement for flows with large Knudsen numbers. To reduce the computation cost, a set of simplified analytical solutions is introduced as well. A cosine-law plume model has improved performance at low Knudsen numbers. However, for more rarefied high-speed rocket plume flows, such as those fired from electric propulsion devices, the newly developed model has relatively better performance. The new analytical solutions further provide velocity, temperature, and pressure results.