Characterization of Candidate Materials for Remote Recession Measurements of Ablative Heat Shield Materials
Characterization of Candidate Materials for Remote Recession Measurements of Ablative Heat Shield Materials
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用于烧蚀热屏蔽材料远程衰退测量的候选材料的表征
DOI：
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
S. Splinter
中科院分区：
文献类型：
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作者：
B. Butler;M. Winter;F. Panerai;Alexandre Martin;S. Bailey;M. Stackpoole;P. Danehy;S. Splinter
在NASA兰利中心的电弧喷射装置上，通过激波后层的发射光谱，对等离子体流中材料样品的表面凹陷进行了远程测量。研究了将种子产物递送到酚醛浸渍碳填料（PICA）材料样品中的不同方法。通过将晶种材料注入到PICA的芯中，或者通过将晶种材料封装在环氧树脂盘中，将盘机械结合到PICA样品上，用Al、Si、HfO2、VB 2、Al2O3、SiO2、TiC、HfC、NaCl和MgCl 2的组合对PICA材料进行晶种，从而产生三个样品。然后，在低压空气等离子体下，在接近2400 K的表面温度下对接种有候选示踪剂的PICA样品进行测试。冲击后层中的Al、Ti、V、Na和Mg的发射在UV中用高分辨率成像光谱仪从侧面观察整个停滞线，并且从UV到NIR用光纤耦合小型光谱仪通过准直器从正面在200 nm至1,100 nm的波长范围内观察样品表面。铝，钠，镁被发现发射在冲击后的光谱，甚至在衰退达到播种深度-因此可能表征热解过程，而不是衰退本身。光谱中Ti和V发射的出现与通过样品前表面的视频监测的实际衰退很好地相关。晶种材料作为衰退指标的适用性似乎与晶种材料的熔融温度有关。未来的参数研究将在肯塔基州大学的低功率等离子体设施中进行。
A method of remotely measuring surface recession of a material sample in a plasma flow through emission spectroscopy of the post shock layer was characterized through experiments in the NASA Langley HYMETS arc jet facility. Different methods for delivering the seed products into the Phenolic Impregnated Carbon Ablator (PICA) material samples were investigated. Three samples were produced by seeding the PICA material with combinations of Al, Si, HfO2, VB2, Al2O3, SiO2, TiC, HfC, NaCl, and MgCl2 through infusing seed materials into a core of PICA, or through encapsulating seed material in an epoxy disk, mechanically bonding the disk to a PICA sample. The PICA samples seeded with the candidate tracers were then tested at surface temperatures near 2400 K under low pressure air plasma. The emission of Al, Ti, V, Na, and Mg in the post-shock layer was observed in the UV with a high resolution imaging spectrometer viewing the whole stagnation line from the side, and from UV to NIR with a fiber-coupled miniaturized spectrometer observing the sample surface in the wavelength range from 200 nm to 1,100 nm from the front through a collimator. Al, Na, and Mg were found to be emitting in the post-shock spectra even before the recession reached the seeding depth - therefore possibly characterizing the pyrolysis process rather than the recession itself. The appearance of Ti and V emission in the spectra was well correlated with the actual recession which was monitored through a video of the front surface of the sample. The applicability of a seed material as an indicator for recession appears to be related to the melting temperature of the seed material. Future parametric studies will be carried out in low power plasma facilities at the University of Kentucky.