In-Situ Ablation Experiments of Cork-based and Carbon Phenolic Thermal Protection Materials in an X-Ray Synchrotron Facility

摘要

The cork based DLR Cork and low density DLR ZURAM materials were exposed to heat while being monitored by x-ray radiation in a synchrotron facility. A portable furnace was manufactured to provide the low pressure conditions of the atmospheric entry and the high stagnation heat fluxes. A total of 4 samples were exposed to radiative heating at 10.4 mbar pressure. The sample was rotated inside the furnace by a miniature servomotor to allow for 3D image reconstruction. Furthermore, 2D radiography sequences were also acquired with stationary samples. The charring, char front propagation and volumetric expansion were prominent in the case of DLR Cork. Even though the ZURAM sample did not significantly char, volumetric phenomena were observed even in the virgin regions. 3D image sequences are provided for ablating DLR Cork material, where the surface topology evolution can be observed. Furthermore, individual cork granules could be tracked throughout the ablation. An optical flow analysis was applied to track the carbon fibers following the volumetric phenomena inside the DLR ZURAM samples.