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隔热毡是高超声速飞行器防热系统中重要的组成部分。隔热毡内存在复杂的多种传热形式的耦合,本文详细地分析了隔热结构内导热与辐射的复合换热问题,用光学厚极限法分析了隔热层纤维席内辐射热流。建立了高温绝热毡有效热导率的数值计算模型,分析了温度和压力对传热机制的影响。该模型预测的有效导热系数与试验结果最大误差不超过6%。通过应用数值分析方法得到有效导热系数,建立了防热结构一维瞬态传热模型,该模型结果与瞬态实验结果最大误差为8%。最后还计算出不同厚度隔热毡蒙皮结构的温度响应,并分析讨论了隔热毡厚度对隔热效果的影响。本文研究表明:TPS隔热毡的厚度达到63.3mm后,继续增加尺寸,其隔热效率将明显降低。
Insulation felts are an important part of the hypersonic aircraft thermal protection system. In this paper, the heat transfer and radiation in the insulation structure are analyzed in detail, and the radiation heat flux in the fiber insulation mat is analyzed by the optical thickness limit method. The numerical model for calculating the effective thermal conductivity of high temperature thermal insulation mat was established and the influence of temperature and pressure on the heat transfer mechanism was analyzed. The model predicts the effective thermal conductivity and the maximum error of the test results does not exceed 6%. By using the numerical analysis method to get the effective thermal conductivity, a one-dimensional transient heat transfer model of heat-resistant structure was established. The maximum error between this model and the transient experiment was 8%. Finally, the temperature response of the skin structure with different thickness was calculated, and the influence of the thickness of the felt on the thermal insulation effect was analyzed. This study shows that: TPS insulation blanket thickness of 63.3mm, continue to increase the size, the thermal insulation efficiency will be significantly reduced.