Development of Advanced Conformal Ablative TPS Fabricated from Rayon- and Pan-Based Carbon Felts

Gasch, Matthew J.; Stackpoole, Mairead; White, Susan; Boghozian, Tane

doi:10.2514/6.2016-1414

Cited by 11 publications

(9 citation statements)

References 5 publications

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“…Examples of variations around the same material class are conformal and flexible carbon/phenolic composites [12,13]. These are manufactured according to a similar infusion processing as that used in heritage rigid ablators.…”

Section: Porous Materials and Microtomography Imagingmentioning

confidence: 99%

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High temperature permeability of fibrous materials using direct simulation Monte Carlo

Borner

Panerai

Mansour

2017

International Journal of Heat and Mass Transfer

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Porous carbon fiber materials are used as effective insulators in many applications where high temperatures are involved. In particular, they are used as the substrate of ablative thermal protection materials for atmospheric entry systems. In this application and in many other industrial uses, quantifying the permeability of porous materials is needed to compute the flow rate of gases through them, under certain environmental conditions. In this work, direct simulation Monte Carlo (DSMC) simulations are used to compute permeability of several fibrous substrates to high temperature gases. The actual porous geometry of the materials is digitized using X-ray microtomography. Numerical results at various pressures and Knudsen numbers are compared with experimental data published in the literature. The method confirms that the pressure dependence of effective gas permeability is well represented by the Klinkenberg formulation.The method is validated by showing close agreement between measurements of permeability from simulations and experimental investigations. Four carbon fiber materials with different microstructures are investigated. We show that the permeability strongly depends on the pore size distribution, as well as on 20 ing the Boltzmann equation. It was originally proposed for rarefied and transitional flows but has since been applied to near-continuum and continuum flows.DSMC can provide an accurate model for the entire boundary layer including the flow within the microstructure, where the size of the fibers may approach the mean-free-path of the flow. As the permeability of a porous material is a 25 function of the distribution of its micropores, in this paper, the computational domain for DSMC simulations is obtained from three-dimensional (3D) images

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Section: Porous Materials and Microtomography Imagingmentioning

confidence: 99%

“…1b), and samples of Calcarb and Morgan carbon felt (Morgan Advanced Materials, Fostoria, Ohio, USA). This felt is one of the candidate precursors for the manufacturing of conformal PICA (C-PICA) [13].…”

Section: Porous Materials and Microtomography Imagingmentioning

confidence: 99%

High temperature permeability of fibrous materials using direct simulation Monte Carlo

Borner

Panerai

Mansour

2017

International Journal of Heat and Mass Transfer

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“…In order to prepare for future exploration missions and to meet the more demanding thermal protection requirements of anticipated atmospheric entries, NASA is improving material response models for low-density carbon/phenolic ablators and developing new material technologies that enable better performance and more effective design. Examples of these technologies are conformal and flexible carbon/phenolic composites [1,2]. The basic architecture is obtained infusing a phenolic resin into an insulating fibrous substrate, following the flight-proven state-of-the-art architecture of the Phenolic Impregnated Carbon Ablator (PICA) [3].…”

Section: Introductionmentioning

confidence: 99%

Micro-tomography based analysis of thermal conductivity, diffusivity and oxidation behavior of rigid and flexible fibrous insulators

Panerai¹,

Ferguson²,

Lachaud³

et al. 2017

International Journal of Heat and Mass Transfer

105

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“…Conformal ablators are manufactured using a modified liquid impregnation procedure originally developed for PICA, SIRCA, and related rigid substrate ablators. 1,10,15 Several variations on the process are outlined in a patent for those materials. 16 In these processes, a fiber substrate is gradually infiltrated by a liquid resin solution in a container under vacuum.…”

Section: B State-of-the-art Processingmentioning

confidence: 99%

“…[12][13][14] State of the art manufacturing for conformal ablative materials uses an open liquid impregnation process adapted from PICA processing in which the fibrous substrate, constrained in the mold, is infused using vacuum-assisted immersion. 1,10 Mold openings are required for proper infiltration of the substrate. Some resin necessarily remains outside the substrate, but is cured along with the part and then removed from the mold and discarded post-process.…”

Section: Introductionmentioning

confidence: 99%

Vacuum Infusion Process Development for Conformal Ablative Thermal Protection System Materials

Sidor

Braun

Beck

et al. 2017

AIAA SPACE and Astronautics Forum and Exposition

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Conformal ablators are low density composite materials comprised of a flexible fibrous substrate and polymer matrix. These materials are fabricated to near net shape by placing the substrate in a rigid, matched mold and infusing with liquid resin in an open, vacuumassisted immersion process. This process, originally developed for older rigid substrate ablators such as PICA, wastes a substantial amount of resin. In this work, a vacuum infusion process -a type of liquid composite molding where resin is directly injected into a closed mold under vacuum -is advanced for conformal ablators. The process reduces waste over the state-of-the-art technique and may eliminate the need for an atmosphere-controlled oven. Small, flat samples of Conformal Phenolic Impregnated Carbon Ablator are infused using the new approach and subjected to a range of curing configurations and conditions. Resulting materials are inspected for quality and compared to material produced using the standard process. Density, resin mass fraction and char yield are measured. Lessons learned inform subsequent plans for process scale up.

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Development of Advanced Conformal Ablative TPS Fabricated from Rayon- and Pan-Based Carbon Felts

Cited by 11 publications

References 5 publications

High temperature permeability of fibrous materials using direct simulation Monte Carlo

High temperature permeability of fibrous materials using direct simulation Monte Carlo

Micro-tomography based analysis of thermal conductivity, diffusivity and oxidation behavior of rigid and flexible fibrous insulators

Vacuum Infusion Process Development for Conformal Ablative Thermal Protection System Materials

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