C/C材料的烧蚀机制分析

On Ablation Mechanism of Carbon/Carbon Material

本文采用两方程模型分析了C/C材料在再入过程中的烧蚀机制,推导了再入过程中双控制下的烧蚀计算公式,并计算了温度在1200K～3500K范围内C/C材料的烧蚀率分布,从而提出了C/C材料在再入过程中各种控制所适用的统一准则,合理地确定了C/C材料在再入过程中各种控制发生的温度范围。本文提出的分析方法还可以推广到碳基材料喷管的热化学烧蚀计算中。

Carbon/Carbon material is commonly used as thermo-protection materialof space shuttle and rocket motor nozzle. He et al calculated ablation of C/Cmaterial during reentry with dynamic control mechanism and two chemicalreactions: C+(1/2)O_2→CO and C+O_2→CO_2 [2]. This method is applicable torelatively low temperature. Bian et al calculated such ablation with doublecontrol mechanism (both diffusion control mechanism and dynamic controlmechanism) and only one chemical reaction: C+(1/2)O_2→CO[5]. This methodis applicable to relative high temperature. In this paper, the authors calculate such ablation with double controlmechanism and two chemical reactions as in reference [2]. This approachrequires rather complicated iterative calculation and is applicable to the entiretemperature range. It gives ablative rates that agree with measured values ofU. S space shuttle. In order to make use of simpler methods of calculation of He et al andBian et al, this paper gives criteria for determining the temperature limits oftheir applicability. For C/C material, below 1910K, the method of He et alcan be used, and above 2850K, the method of Bian et al or methods based ondiffusion control mechanism such as that of Wu et al [6] can be used. This paper's method can also be used to study the thermochemical ablationmechanism for other materials and other thermo-protection environments.