Development and validation of skeletal/global mechanisms describing TMP-based flame inhibition

Phosphorus-based chemical compounds such as trimethylphosphate (TMP) and dimethylmethylphosphonate (DMMP) are widely used as fire suppressants. The detailed chemical kinetic mechanism by Jayaweera et al. [1] is frequently used to describe the flame inhibition process. The elementary reaction steps can be categorised into inhibitor molecule decomposition steps and radical recombination steps. The present work shows that the inhibitor decomposition process can be adequately represented by a single irreversible step for TMP. Subsequently, graph-based mechanism reduction techniques and sensitivity analysis are employed to extract the key catalytic inhibition reactions. The resultant skeletal kinetic mechanism consists of 4 species and 7 reactions. The present work also proposes a global mechanism containing 3 species and 3 reactions. In the global model, flame inhibition is described by a 2-step model. These models are validated in premixed and diffusion flame environments. Excellent agreement with the experimental measurements and detailed model predictions are obtained. Development of the skeletal/global models reduces the computational time by around 82% compared to the detailed model.

含磷化合物（如磷酸三甲酯（trimethylphosphate, TMP）与甲基膦酸二甲酯（dimethylmethylphosphonate, DMMP））被广泛用作灭火剂。Jayaweera等[1]提出的详细化学动力学机理常被用于描述火焰抑制过程。该机理中的基元反应步骤可分为抑制剂分子分解步骤与自由基复合步骤。本研究表明，对于TMP，其抑制剂分解过程可通过单一不可逆步骤实现合理表征。随后，本研究采用基于图的机理简化技术与敏感性分析方法，提取得到核心催化抑制反应。最终构建的骨架动力学机理包含4种组分与7个基元反应。本研究同时提出了包含3种组分与3个反应的全局机理模型。在该全局模型中，火焰抑制过程通过两步模型进行描述。上述模型均在预混火焰与扩散火焰环境中完成了验证，其结果与实验测量值及详细机理模型的预测结果均具有极佳的一致性。相较于详细机理模型，该骨架/全局机理模型可将计算时长缩短约82%。