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本文对碳酚醛和硅酚醛复合材料在持续加热条件下的烧蚀,作了实验和分析研究。试件面积最大达8.75英寸~2,其中装有埋入的热电偶。试样的特性利用两台空气电弧加热器在台阶形热脉冲加热下显示出来。脉冲持续时间是5分钟(2台阶),或是1.4分钟(达5个台阶)。额定峰值热载荷为35,000英热单位/英尺~2。对于二台阶、低剪切力(达2.5磅/英尺~2)的一组试验来说,其内部温度、表面温度、表面后退率和残留碳化层内的烧蚀图象均正常。对于碳酚醛材料,碳化烧蚀理论得出的内部温度及表面温度响应与实验结果很一致。五台阶、中等峰值剪切力(30磅/英尺~2)条件下,电影胶片清楚地表明,在后面的几次试验中存在微机械表面剥蚀。进而利用改变差量的办法,微机械剥蚀效应也与理论相一致。结果发现,为了精确地模拟持续加热烧蚀,需要可靠的复合材料特性值。
In this paper, the experimental and analytical studies on the ablation of carbon-phenolic aldehydes and silicon-phenolic composites under the conditions of continuous heating were carried out. Specimen area up to 8.75 inches ~ 2, which is embedded with a thermocouple. The characteristics of the sample are shown with two air arc heaters heated by a stepped heat pulse. Pulse duration is 5 minutes (2 steps), or 1.4 minutes (up to 5 steps). Rated peak thermal load of 35,000 Btu / ft2. For a set of tests with two steps, low shear (up to 2.5 psi), the internal temperature, surface temperature, surface back-off rate, and ablation images in the residual carbide layer were all normal. For carbon phenolic materials, the internal temperature and surface temperature response from the carbonized ablation theory is in good agreement with the experimental results. With five steps and moderate peak sheer force (30 psi / 2), the motion picture clearly shows that there are micro-mechanical surface ablations in the next few trials. And then use to change the difference approach, micro-mechanical erosion effect is also consistent with the theory. The results showed that in order to accurately simulate continuous heating ablation, reliable composite material properties were required.