KY Space Grant GF-22-025: Measurement of permeability and tortuosity for charred TPS samples

An experimental facility for measuring the permeability of thermal protection system materials has been constructed at UK under prior NASA funding. The system has been validated against measurements of well characterized materials including fiberform. Initial measurements of permeability for other samples of interest to NASA have been conducted with results regularly with collaborators. The facility has been recently upgraded to permit measurements of tortuosity for which experimental data on these materials does not exist. In the proposed project, measurements of permeability and tortuosity will be conducted for virgin samples of candidate TPS materials with NASA guidance. For the first time, measurements will also be conducted on samples that have undergone partial charring to represent conditions during the ablation process and characterize the change in flow properties that occur during dynamic material degradation. Samples of charred materials will both be provided directly by NASA collaborators and be generated in our laboratory with an available furnace, as described in the commitment letters. The materials, sampling conditions, and resulting measurements will be reported to NASA collaborators at regularly scheduled meetings. These measurements will be conducted by the Graduate Fellowship recipient, Mr. John Ryan O’Nan. During this funding period he will complete requirements for the M.S. in Aerospace Engineering. Mr. O’Nan has been responsible for upgrading the facility for tortuosity measurements and has completed preliminary measurements as described in this proposal.