Analysis of Ionization Reactions in Chemical Reaction Models of Hypersonic Re-entry Vehicles

Abstract During the re-entry vehicles returning to Earth, the plasma sheath forms around the vehicle, causing the “blackout” phenomenon. To accurately simulate the plasma sheath, an accurate chemical reaction model is required. This study employs computational fluid dynamics (CFD) simulations with chemical reactions for the RAM-C-II re-entry vehicle and utilizes sensitivity analysis to analyze the ionization reactions in the stagnation line. This study finds that the associative ionization reaction involving nitrogen (N) atom and oxygen (O) atom is the dominant reaction, while charge exchange reactions between N atoms and O atoms can be neglected. The O atoms’ and N atoms’ associative ionization reactions are secondary. Based on these findings, the chemical reaction model for re-entry vehicles can be simplified to include only three associative ionization reactions, excluding charge exchange reactions from consideration.