Numerical study on aerodynamic characteristics of Mars parachute system with different combinations of fabric permeability and structural porosity

Supersonic parachute plays a crucial role in Mars exploration missions. However, future's large payload exceeds the maximum allowed one of disk-band-gap parachute, new generations of supersonic disksail and ringsail parachute had failed in their flight tests, which may be related to their complicated permeabilities (fabric permeability and structural permeability). Till now, most effects on fabric permeability are mostly considered in subsonic flows, and the influence mechanism of fabric permeability under supersonic conditions is rarely reported. In this study, different permeability schemes (including fabric and structural permeabilities) are designed for a supersonic disksail parachute system. The influence of different ratio of structural permeability to fabric permeability under same total porosity on the flow fields around a parachute system and aerodynamic performance is compared and analyzed. As a result, when the ratio of structural permeability to fabric permeability is 5:5, the stability of parachute shows better than other air permeability schemes. When the ratio is 7:3, the canopy has the best drag performance. With the contribution of fabric permeability increased from 30% to 70%, the drag performance of parachute presents a decreasing trend. Then, the porosity schemes with better aerodynamic performance are placed under Martian atmosphere conditions. The results show that in supersonic flows, when the ratio is 7:3, the aerodynamic performance of parachute is better. In transonic stage, the parachute with ratio of 7:3 has better drag performance, while the parachute with ratio of 5:5 has better stability. In subsonic stage, the parachute with ratio of 5:5 has better drag and stability performance.