Study on the Impact of Wall Degradation on the Performance of Air-Breathing Electric Propulsion Intake and Its Optimization Design

The Air-Breathing Electric Propulsion (ABEP) system, as a critical technology, provides a sustainable propulsion solution for ultra-low Earth orbit (ULEO) satellites by capturing sparse atmospheric molecules as propellant. The intake duct, as the core component of the ABEP system, plays a pivotal role in determining the overall effi0ciency of the system. In this study, the Direct Simulation Monte Carlo (DSMC) method is employed, and the wall accommodation coefficient (σ) is introduced to simulate the evolution of wall reflection modes. The variations in the intake performance of the D-MDAR and ESA intake ducts during the wall degradation process are investigated. The results reveal that as the wall reflection characteristics evolve from specular reflection (σ=0) to diffuse reflection (σ=1), both capture efficiency and compression ratio exhibit significant degradation. For example, in the D-MDAR intake, the capture efficiency drops from 66.28% to 37.87%, and the compression ratio increases from 9.8 to 30.3. Similarly, in the ESA intake, the capture efficiency decreases from 22.53% to 6.21%. To address this issue, two optimized designs, LD-MDAR and H-ESA, are proposed. The capture efficiency of LD-MDAR increases to 52.8%, and the compression ratio reaches 24.24, while H-ESA achieves a capture efficiency of 17.35% and a compression ratio of 24.61. The optimized designs significantly improve the performance of the intake ducts in actual orbital environments. This study provides theoretical support and practical guidance for the performance degradation assessment and long-term lifetime design of ABEP intake ducts.