High-Temperature Spectrometer for Thermal Protection System Radiation Measurements

摘要

To better characterize the response of thermal protection systemmaterials to predicted near-infrared shock layernradiation, a new experimental system was developed to extend the measurement range of radiation transportnparameters to high-temperature environments and relatively high-radiation fluxes. A portable research-gradenspectrometer was coupled with fiber optics in order to operate in a variety of harsh operating environments.nExperimental results are presented from tests performed at the solar tower, which provided broadband nonpulsednvisible and infrared radiation at relatively high-flux levels. Data from three low-density porous refractory fibrousnmaterials are presented, including two shuttle tile materials (fibrous refractory composite insulation and LockheednInternational) and one carbon fibermaterial. The results showed that thin 1 and 2 mm specimens of the ceramic tilenmaterials acted as robust high-temperature gray filters in the near infrared, whereas thicker tile specimens (andn1mmand thicker porous carbon fibermatrix samples tested) absorbed the incident radiation strongly and exhibitednonly thermal radiation spectral profiles.