Characterization of candidate materials for remote recession measurements of ablative heat shield materials

Bradley D. Butler, Michael Winter, Francesco Panerai, Alexandre Martin, Sean C.C. Bailey, Margaret Stackpoole, Paul M. Danehy, Scott Splinter

Research output: Contribution to conferencePaperpeer-review

12 Scopus citations

Abstract

A method of remotely measuring surface recession of a material sample in a plasma flow through emission spectroscopy of the post shock layer was characterized through experiments in the NASA Langley HYMETS arcjet facility. Different methods for delivering the seed products into the Phenolic Impregnated Carbon Ablator (PICA) material samples were investigated. Three samples were produced by seeding the PICA material with combinations of Al, Si, HfO2, VB2, Al2O3, SiO2, TiC, HfC, NaCl, and MgCl2 through infusing seed materials into a core of PICA, or through encapsulating seed material in an epoxy disk, mechanically bonding the disk to a PICA sample. The PICA samples seeded with the candidate tracers were then tested at surface temperatures near 2400 K under low pressure air plasma. The emission of Al, Ti, V, Na, and Mg in the post-shock layer was observed in the UV with a high resolution imaging spectrometer viewing the whole stagnation line from the side, and from UV to NIR with a fiber-coupled miniaturized spectrometer observing the sample surface in the wavelength range from 200 nm to 1,100 nm from the front through a collimator. Al, Na, and Mg were found to be emitting in the post-shock spectra even before the recession reached the seeding depth - therefore possibly characterizing the pyrolysis process rather than the recession itself. The appearance of Ti and V emission in the spectra was well correlated with the actual recession which was monitored through a video of the front surface of the sample. The applicability of a seed material as an indicator for recession appears to be related to the melting temperature of the seed material. Future parametric studies will be carried out in low power plasma facilities at the University of Kentucky.

Original languageEnglish
DOIs
StatePublished - Jan 4 2016
Event54th AIAA Aerospace Sciences Meeting, 2016 - San Diego, United States
Duration: Jan 4 2016Jan 8 2016

Conference

Conference54th AIAA Aerospace Sciences Meeting, 2016
Country/TerritoryUnited States
CitySan Diego
Period1/4/161/8/16

Bibliographical note

Funding Information:
The work on remote recession measurements and development of facilities and methods for the investigation of gas-surface interactions is supported by NASA Kentucky under NASA awards No: NNX10AL96H and No: NNX13AB12A, and by NASA Ames through the research grant NNX15AN74A. Financial support for the experimental work at NASA Langley was provided by NASA Kentucky EPSCoR Award NNX10AV39A. The authors would like to thank Michael Wright and Nagi Mansour from NASA Ames Research Center, Floyd Taylor and Herb Mefford at the University of Kentucky for their assistance in designing and machining many of the components necessary for this project, Zhaojin Diao and Helmut Koch for their help in preparing the measurement campaign, Gregory Gonzales, Joe Wang, Joel Seibert, and Joe Mach for their support at NASA Ames, and Jeff Gragg for his support and cooperation during testing at NASA Langley.

Publisher Copyright:
© 2016, American Institute of Aeronautics and Astronautics Inc, AIAA. All Rights Reserved.

ASJC Scopus subject areas

  • Aerospace Engineering

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