低温炭化烧蚀材料的导热系数随材料的结构、工艺及使用中加热速率的不同而变化。我们采用非稳态的测试方法,利用等离子体射流加热试件,造成近于真实的烧蚀环境,得到比较真实的导热系数。 测试原理 烧蚀后的低温炭化防热材料一般分为炭化区、热解区和原始材料区。经过简化假定,可以列出描述这三个区域物理模型的微分方程。原始材料的导热系数直接影响防热层的温度分布,但若利用三个区的整套方程通过多次计算来摸清它的准确影响,不但计算量过大,而且也无法排除许多其它因素的影响。因而我们按下述原理拟定试验 The thermal conductivity of low-temperature carbonized ablative material varies with the structure of the material, the process and the heating rate in use. We use unsteady test methods, the use of plasma jet heating specimen, resulting in near real ablation environment, get a more realistic thermal conductivity. Test principle After ablation low temperature carbonization heat-resistant materials are generally divided into carbonization zone, pyrolysis zone and the original material area. After simplifying the assumptions, we can list the differential equations that describe the physical models of the three regions. The thermal conductivity of the original material has a direct impact on the temperature distribution of the heat-proof layer. However, using the entire set of equations for the three regions to find out its exact effect through multiple calculations, it is not only computationally intensive but also can not eliminate the influence of many other factors . Therefore we draw up the experiment according to the following principle