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Initial particle ejection behaviours due to a hypersonic jet impingement at different high-nozzle pressure ratios in rarefied atmospheric conditions
Ist Teil von
Acta astronautica, 2024-09, Vol.222, p.126-135
Ort / Verlag
Elsevier Ltd
Erscheinungsjahr
2024
Link zum Volltext
Quelle
Alma/SFX Local Collection
Beschreibungen/Notizen
Understanding particle ejection behaviours in plume-regolith interaction is important for a safe soft-landing system and landing manoeuvre in planetary missions. In this study, a Mach 5.8 hypersonic jet at the different Reynolds numbers of 2.58 × 104 and 9.35 × 102 impinges on the deposited glass particles of 80 μm diameter in a vacuum chamber, and the particle and gas motions at the nozzle pressure ratios (NPR) of 95, 950, and 1900 are investigated using the time-resolved PIV and high-speed Schlieren techniques. A narrow hypersonic jet consisting of several shock cells forms at the lower NPR of 95 and causes a deeply narrow crater due to its jet penetration into the deposited particles. The deeply narrow crater makes a particle ejection angle increase upwardly. On the other hand, a relatively wide crater forms due to the jet impingement at the other NPR conditions which a widely long shock cell is generated. Based on the present experimental results, a dominant factor in particle ejection angle is the crater size and depth, whereas a particle diffusion velocity is dominated by surrounding pressure. The diffused particles move faster in a low surrounding pressure because of a low aerodynamic drag force acting on the diffused particles.
•A dominant factor in particle ejection angle is the crater size and depth.•The diffused particles move faster in a low surrounding pressure.•The particle and gas motions at several NPRs are investigated in a vacuum chamber.