Thermal Modeling and Experimental Characterization of a Facility for Testing Materials in Simulated Reentry Profiles

With new reentry vehicles being developed to fly advanced trajectories, added emphasis has been placed on developing novel Thermal Protection Systems (TPS) that can withstand these trajectories while providing adequate performance as an insulator. Many of these TPS candidates are in the development stage, and material manufacturers are interested in obtaining thermal response data prior to investing in more costly evaluations such as ground tests in arc heaters. To help provide feedback to material developers as well as program sponsors, a facility has been developed that is capable of providing thermal response data for advanced TPS materials under simulated temperature and pressure reentry profiles. The design of the facility was optimized using both experimental and numerical modeling components or analysis during its development. The optimized facility is capable of producing temperatures as high as 4500 F with pressures as low as 100 mTorr in inert atmosphere. A PID algorithm is used to simulate reentry profiles at heating rates up to 300 F/min. Specimen surface temperatures are measured with pyrometers, while in-depth thermal responses are recorded using Type-K thermocouples. Bourdon, Piezo, Thermocouple, and Pirani pressure gages are used to record chamber pressures with redundant instrumentation in place to verify all readings.