| 基于多场耦合碳/碳复合材料传热及烧蚀响应 |
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| 作者姓名： | 孙学文 杨海波 米涛 |
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| 作者单位： | 1.北京科技大学机械工程学院，北京 100083 |
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| 基金项目： | 国家重大科学仪器设备开发专项资助项目（2011140145）；河北省科技厅资助项目（17211117） |
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| 摘 要： | 碳/碳复合材料作为热防护材料多用在高超声速飞行器鼻锥、机翼前缘等位置。为准确预测其传热及烧蚀响应，采用多场耦合策略，考虑外部流场热化学非平衡效应、固体材料传热以及材料表面烧蚀，建立高超声速气动热环境下碳/碳复合材料的流?热?烧蚀多场耦合模型，预测碳/碳复合材料瞬态温度场分布、烧蚀速率以及烧蚀外形变化等。计算得到材料模型驻点区壁面温度和热流值随着时间的推移发生了显著的变化，初始时刻热流值较大，1 s时驻点热流密度为17.22 MW?m?2，随着时间推移，壁面温度增大，驻点区温度梯度减小，热流值也减小，30 s时驻点热流密度为10.22 MW?m?2。材料模型驻点区的温度较高，材料表面反应活跃，烧蚀较为严重，而模型侧面只发生少量烧蚀，烧蚀前后材料模型外形发生一定的变化，前缘半径增大，30 s时材料驻点烧蚀深度为17.47 mm。结果表明:在高超声速气动热环境下，碳/碳材料模型发生一定的烧蚀后退，导致外部流场以及热载荷发生变化，采用流?热?烧蚀多场耦合模型可有效预测不同时刻材料的传热及烧蚀响应，为热防护系统的设计提供一定的参考。
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| 关 键 词： | 高超声速 碳/碳复合材料 热防护材料 烧蚀 多场耦合 数值模拟 |
| 收稿时间： | 2019-06-30 |
Heat transfer and ablation of carbon/carbon composites based on multi-field coupling |
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| Affiliation: | 1.School of Mechanical Engineering, University of Science and Technology Beijing, Beijing 100083, China2.Key Laboratory of Fluid Interaction with Material of Ministry of Education, University of Science and Technology Beijing, Beijing 100083, China3.Centre of Excellence for Advanced Materials, Dongguan 523808, China4.School of Materials Engineering, North China Institute of Aerospace Engineering, Langfang 065000, China |
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| Abstract: | With the development of hypersonic technology, the demand for thermal protection material is continuously increasing. Carbon/carbon composites are widely used as thermal protection materials in the nose and in the leading edge of hypersonic vehicles owing to their high latent heat and good resistance to high temperatures. The flow field around the aircraft affects the heat transfer and ablation of carbon/carbon composites, changing the thickness and shape of the thermal protection layer. The ablation of carbon/carbon composites alters the flow field distribution, thus conversely affecting the ablation of carbon/carbon composites. To predict the heat transfer and ablation of carbon/carbon composites, a multi-field coupling model was established to predict the transient temperature distribution, ablation rate, and ablation profile of carbon/carbon composites in hypersonic aerothermal environments. The thermochemical non-equilibrium effects of the flow field, heat transfer of the material, and ablation of the material surface were considered in the modeling. The wall temperature and heat flux in the stagnation area change significantly. The initial heat flux is higher and the stagnation heat flux at 1 s is 17.22 MW?m?2. As time passes, the wall temperature increases, the temperature gradient in the stagnation area decreases, the heat flux decreases, and the stagnation heat flux at 30 s is 10.22 MW?m?2. As the temperature of the stagnation area is high, the material at the surface reacts actively and the ablation is more serious, whereas only a small amount of ablation occurs on the side of the model. The shape of the material model changes after the ablation, the leading-edge radius increases, and the ablation depth at the material stagnation point is 17.47 mm at 30 s. The results show that, in the hypersonic aerodynamic thermal environment, the carbon/carbon composites have a certain ablation recession, which leads to change in the external flow field and thermal load. The multi-field flow-heat-ablation coupling model can be used to predict the response of thermal protection materials, which can provide some reference for the design of thermal protection systems. |
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