Interactions of Single-Nozzle Sonic Propulsive Deceleration Jets on Mars Entry Aeroshells

摘要

As themass and landing site altitude of futureMars entry systems increase, the size requirements for conventionalnaerodynamic decelerators are becoming unfeasible. One option is propulsive decelerator jets. The use of propulsivendecelerator jets, however, involves complex flow interactions that are still not well understood. This paper describesnnumerical and experimental techniques currently used to investigate these interactions. The paper also presentsncomputational results for single-nozzle sonic propulsive decelerator jets. The numerical simulations use a scalednMars Science Laboratory aeroshell in Mach 12 laminar flow of I2-seeded N2 gas. The results show that flowfieldnfeatures, such as the bowand propulsive decelerator jet shocks, are affected by the thrust coefficient of the propulsivendecelerator nozzle. These effects also extend to the surface and aerodynamic properties of the aeroshell.As the thrustncoefficient increases, the pressure and shear stress approach roughly constant values over most of the aeroshellnsurface, and the drag coefficient decreases and approaches a constant value equal to approximately 8%of the valuenfor the propulsive decelerator jet-off case. Finally, comparisons between the numerical results and experimental datanshow good agreement in the bow shock profile and standoff distance, as well as the aerodynamic properties of thenaeroshell.