Deployment And Performance Characteristics Of 15 Meter Supersonic Attached Inflatable Decelerators

Author : Alejandro Pensado
Publisher :
ISBN 13 : 9780355149388
Total Pages : pages
Book Rating : 4.1/5 (493 download)

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Download or read book Scalability of a Tension Cone Supersonic Inflatable Aerodynamic Decelerator written by Alejandro Pensado and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Human-class missions to Mars will require larger and safer payloads than current technology can achieve. The inflatable aerodynamic decelerator concept has the potential to meet these needs which will enable human-class missions to Mars for a desired 2030s window. This concept, started in the 1960s for the Viking missions, involves a deployable inflatable aeroshell designed for missions with entry, descend and land stages. Research fluctuated in the following decade from minor development in the 1980s to an increased interest in recent years including international entities. The continuing research resulted in two major designs: Supersonic and hypersonic decelerators. The objective of this thesis is to systematically study the scalability of the supersonic inflatable aerodynamic decelerator tension cone and computationally simulate the minimum inflation pressure required for Earth and Mars deployment conditions. The scalability study is based on the 0.6-meter diameter tension cone model studied in the supersonic wind tunnel tests conducted at NASA Glenn Research Center. The scaling parameters chosen to investigate the deployment performance of 14, 17, 20, and 23-meter tension cones are Reynolds number, Froude number, ballistic coefficient, and mass efficiency at a fixed Mach number. Scaling the Reynolds number showed the tension cones operate under laminar flow conditions. Matching the Froude number determined that a larger tension cone is more effective in decelerating the entry vehicle and less effective in a Mars atmosphere compared to an Earth atmosphere. Both the ballistic coefficient and mass efficiency showed that a larger tension cone is less efficient at decelerating because the mass increase of the tension cone overwhelms the effect of increasing the diameter of the tension cone. The velocity to match each scaling parameter was calculated for the 0.6-meter model. These results were compiled into eight potential case studies to investigate the tension cone at these deployment conditions.The objective of the simulations was to determine time history of forces at the scaled conditions, inflation pressure required for deployment, and minimum inflation pressure required to prevent buckling. The computational work focused on the Earth and Mars cases for the 0.6-meter tension cone with the scaled conditions to match the 14-meter tension cone. Matching the Mach number was used as the validation, where the simulation and experimental axial forces agreed with minimal error. In order to determine the inflation pressure required for deployment, the internal pressure of the torus was reduced until the tension shell began to wrinkle. Wrinkles indicate structural failure and eventual torus buckling. The Mach, Reynolds, and Froude number simulations yielded similar results. Fully deployed, the tension cone had small oscillations, wrinkling appeared and became more prominent as the structure began to fail until the torus buckled. The mass efficiency simulation experienced higher axial force, resulting in more violent tension cone oscillations. The torus experienced a bending moment until the structure buckled. This indicates the axial force load limit on the tension cone. The data were compiled shows a linear relationship between minimum torus inflation pressure and axial loading. This allows tension cone mass optimization for future designs.