| 引用本文: | 张威,曾明,肖凌飞,等.碳-酚醛材料烧蚀热解对再入流场特性影响的数值计算.[J].国防科技大学学报,2014,36(4):41-48.[点击复制] |
| ZHANG Wei,ZENG Ming,XIAO Lingfei,et al.Numerical study for the effects of ablation and pyrolysis on the hypersonic reentry flow[J].Journal of National University of Defense Technology,2014,36(4):41-48[点击复制] |
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| 碳-酚醛材料烧蚀热解对再入流场特性影响的数值计算 |
| 张威, 曾明, 肖凌飞, 徐丹 |
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(国防科技大学 航天科学与工程学院， 湖南 长沙 410073)
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| 摘要: |
| 数值模拟存在碳-酚醛材料烧蚀的高超声速再入流场，分析烧蚀和热解对流场热化学参数、电子数密度分布等的影响。采用19组元双温度的热化学模型，耦合热化学非平衡流 Navier-Stokes方程组和烧蚀壁面边界条件，进行定常烧蚀流场求解；通过对比无烧蚀、非催化和辐射平衡壁温条件下的流场分析烧蚀的影响；讨论了壁面处碳 -酚醛材料热解产物化学组成的确定方法，研究了不同热解率的影响。以 RAM-C球锥的两个典型飞行条件（速度 7.65km/s、高度 61km和 71km）为代表的研究表明：最主要的烧蚀热解产物是 CO、 H2、 H，烧蚀产物和烧蚀的影响均局限于边界层内；烧蚀使原子和离子组元含量下降，当离子组元含量峰值出现在边界层内时，烧蚀使电子数密度峰值下降；随热解率增加烧蚀影响程度增强，烧蚀在后身区影响范围大于头部区，随飞行高度增加烧蚀影响范围扩大。 |
| 关键词: 高超声速非平衡流 数值模拟 烧蚀 石墨 碳-酚醛 |
| DOI：10.11887/j.cn.201404008 |
| 投稿日期：2013-11-15 |
| 基金项目:国家自然科学基金资助项目（1110223） |
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| Numerical study for the effects of ablation and pyrolysis on the hypersonic reentry flow |
| ZHANG Wei, ZENG Ming, XIAO Lingfei, XU Dan |
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(College of Aerospace Science and Engineering, National University of Defense Technology, Changsha 410073, China)
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| Abstract: |
| Through numerically simulating the hypersonic reentry flow with ablation of carbon-phenolic heat-shield, the effects of ablation and pyrolysis on the thermochemical properties and electron densities of the flowfield were analyzed. 19 chemical species were considered and a two-temperature model was taken to describe the thermal nonequilibrium. The Navier-Stokes equations of thermochemical nonequilibrium flow coupled with the ablating boundary condition were solved to obtain the steady-state solution of the flowfiled. The effects of ablation were shown in comparison with the non-ablating baseline case, which has a non-reacting, non-catalytic wall and equilibrium radiation wall temperature. The method to determine surface chemical composition of the pyrolysis gas was discussed, and the effects of the pyrolysis ratio were investigated. The simulation and analysis performed on RAM-C model at flight speed of 7.65km/s and altitude of 61km or 71km show that, the dominant ablation and pyrolysis species are CO, H2 and H, and both the ablation species and the effects of ablation are limited to the boundary layer. The mass fractions of atoms and ions decline as a result of ablation and this may result in the decrease of the peak values of electron density when they appear in the boundary layer. Furthermore, the ablation effects become more pronounced as the pyrolysis ratio rises, and the effects extend further into the flowfield with increasing distance from the stagnation point or with higher flight altitude. |
| Keywords: `hypersonic nonequilibrium flow numerical simulation ablation graphite carbon-phenolic |
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