For space missions involving atmospheric entry, a thermal protection system is essential to shield the spacecraft and its payload from the severe aerothermal loads. Carbon/phenolic composite materials have gained renewed interest to serve as ablative thermal protection materials (TPMs). New experimental data relevant to the pyrolytic decomposition of the phenolic resin used in such carbon/phenolic composite TPMs have recently been published in the literature. In this paper, we infer from these new experimental data an uncertainty-quantified pyrolysis model. We adopt a Bayesian probabilistic approach to account for uncertainties in the model identification. We use an approximate likelihood function involving a weighted distance between the model predictions and the time-dependent experimental data. To sample from the posterior, we use a gradient-informed Markov chain Monte Carlo method, namely, a method based on an Ito stochastic differential equation, with an adaptive selection of the numerical parameters. To select the decomposition mechanisms to be represented in the pyrolysis model, we proceed by progressively increasing the complexity of the pyrolysis model until a satisfactory fit to the data is ultimately obtained. The pyrolysis model thus obtained involves six reactions and has 48 parameters. We demonstrate the use of the identified pyrolysis model in a numerical simulation of heat-shield surface recession in a Martian entry.

中文翻译：

---

贝叶斯识别热保护材料的热解模型参数使用自适应梯度通知采样算法并应用于火星大气条目

对于涉及进入大气层的太空任务，热保护系统对于保护航天器及其有效载荷免受严重的空气热负荷至关重要。碳/酚醛复合材料作为烧蚀热保护材料 (TPM) 重新引起人们的兴趣。与这种碳/酚醛复合材料 TPM 中使用的酚醛树脂的热解相关的新实验数据最近已在文献中发表。在本文中，我们从这些新的实验数据中推断出一个不确定性量化的热解模型。我们采用贝叶斯概率方法来解释模型识别中的不确定性。我们使用近似似然函数，该函数涉及模型预测和时间相关实验数据之间的加权距离。从后部采样，我们使用梯度通知马尔可夫链蒙特卡罗方法，即基于伊藤随机微分方程的方法，并自适应选择数值参数。为了选择要在热解模型中表示的分解机制，我们通过逐步增加热解模型的复杂性来进行，直到最终获得与数据的满意拟合。由此获得的热解模型涉及六个反应，具有 48 个参数。我们演示了在火星进入的隔热罩表面衰退的数值模拟中使用已识别的热解模型。我们通过逐步增加热解模型的复杂性来进行，直到最终获得对数据的满意拟合。由此获得的热解模型涉及六个反应，具有 48 个参数。我们演示了在火星进入的隔热罩表面衰退的数值模拟中使用已识别的热解模型。我们通过逐步增加热解模型的复杂性来进行，直到最终获得对数据的满意拟合。由此获得的热解模型涉及六个反应，具有 48 个参数。我们演示了在火星进入的隔热罩表面衰退的数值模拟中使用已识别的热解模型。