金属热防护系统边缘热短路研究

研究了金属热防护系统(TPS)的缝隙辐射及支架两大热短路问题。通过数值计算分析了缝隙宽度和缝隙辐射率对热短路的影响,完成了整体样件以及阵列组合件的稳态传热实验测试,定量地研究了热短路的影响情况。实验结果显示:支架处热短路现象明显,实验中支架引发的热短路温差高达50K;在773K以下,缝隙传热引发的温升随着缝隙宽度的增加而线性增加;在773K以上,辐射热传导在缝隙宽度超过3mm时即成为内部传热的主导机制,这时缝隙传热引发的温升不再随宽度增加而线性递增。所提供的数值分析和实验方法可为金属热防护系统的分析与设计提供重要的参考价值。

Study on Edge Heat Shorts of Metallic Thermal Protection Systems

The two major heat short problems of gap radiation and brackets in metallic thermal protection system (TPS) are studied in this article. Numerical analysis is carried out to evaluate the influence of gap width and emissivity on heat shorts. A series of steady heat transfer experiments on TPS sample and array is completed, and the influence of heat shorts on performance of TPS is studied quantificationally. The experimental results show that heat shorts occur at the site of brackets, and the resulting temperature difference is as high as 50 K. When the temperature is lower than 773 K, the temperature difference induced by gap heat transfer increases linearly as the gap width becomes larger. When the temperature is higher than 773 K, however, the radiation phenomenon becomes a dominant factor influencing the mechanisms of heat transfer as the gap width is larger than 3 mm. And the temperature difference does not change linearly as the gap width increases. The numerical and experimental methods presented in this study can provide some reference for the design and analysis of metallic TPS.