Archived
This content is available here for research, reference, and/or recordkeeping.
Author ORCID Identifier
https://orcid.org/0009-0002-0104-5844
Date Available
5-1-2026
Year of Publication
2026
Document Type
Doctoral Dissertation
Degree Name
Doctor of Philosophy (PhD)
College
Engineering
Department/School/Program
Mechanical Engineering
Faculty
Michael Renfro
Faculty
Jonathan Wenk
Abstract
Porous thermal protection systems (TPS) used in hypersonic vehicles exhibit coupled gas and radiative transport across multiple regimes and length scales. Accurate performance prediction requires reliable characterization of permeability, slip-flow behavior, and radiative transport properties, particularly for low-permeability and charred materials where existing data are limited. This dissertation presents experimental methods for characterizing multiphysics transport in porous TPS materials. A modular flow system was developed to measure permeability and slip behavior in both virgin and charred materials under relevant environments. A transient pressure decay method enables accurate permeability estimation in low-permeability regimes and provides insight into effective pore structure. Results show that conventional slip-flow models overpredict permeability at elevated Knudsen numbers, while the proposed approach captures transport behavior more reliably. Radiative transport properties were characterized using wavelength-resolved transmission, reflection, and scattering measurements. Analysis indicates that attenuation is strongly influenced by fibrous microstructure, with scattering contributing significantly beyond absorption alone. These methodologies provide validated transport parameters and datasets that improve predictive modeling of TPS performance in hypersonic environments.
Digital Object Identifier (DOI)
https://doi.org/10.13023/etd.2026.116
Archival?
Archival
Funding Information
This work was supported by the National Aeronautics and Space Administration under award Nos. 80NSSC21K0286, 80NSSC20M0047, 80NSSC24M0153, and NASA EPSCoR FY22.
Recommended Citation
Hakim, Yejajul, "Multiphysics Transport in Porous Thermal Protection Systems: Experimental Characterization of Gas Permeability and Radiative Properties" (2026). Theses and Dissertations--Mechanical Engineering. 256.
https://uknowledge.uky.edu/me_etds/256
Included in
Aerodynamics and Fluid Mechanics Commons, Heat Transfer, Combustion Commons, Space Vehicles Commons, Structures and Materials Commons
