基于多组分热解气体的典型炭化固体可燃物火蔓延机理及模型研究

Pyrolysis gas is an important factor to couple the pyrolysis and combustion in the solid fire spread. In fact, multiple pyrolysis gases with different physicochemical characteristics are involved in the combustion and have an effect on the fire spread, while the current researches are focus on the single pyrolysis gas. So, this project is to reveal the fire spread mechanism of typical charring combustible solid wood and develop new models based on the multiple pyrolysis gases..(1)To reveal the relationship among the produced multiple pyrolysis gases and the main three components of wood (hemicellulose, cellulose and lignin) as well as temperature, and develop a prediction model..(2)To develop new models (combustion model, radiation model, soot model, et al.) for combustion stage based on multiple pyrolysis gases and a new solver to simulate the fire spread, revealing the interaction and evolution between the pyrolysis gas flow field and the combustion flow field..The new findings of this project will be a supplement to the current theory of fire spread, fill the gaps of pyrolysis gases and couple the gas-solid boundary with a remarkable contribution. Meanwhile, the developed models and solver will cover the shortage of numerical simulation to provide some reference values for predicting the fire spread in the forest and building fires.

热解气体是固体火蔓延中固相热解和气相燃烧阶段耦合的关键因素，真实火蔓延过程往往包含多种组分的热解气体，不同热解气体表现出不同的物化特性进而影响火蔓延行为，但现有研究主要针对单一组分的热解气体。本项目拟基于多组分热解气体，研究典型炭化固体可燃物木材的火蔓延机理及相关模型：.（1）揭示木材固相热解阶段生成的多组分气体随半纤维素、纤维素和木质素三种组分以及温度的演化机理，并建立预测模型；.（2）建立基于多组分热解气体的气相燃烧阶段模型（燃烧模型、辐射模型、烟模型等）及完整的火蔓延求解器，模拟揭示竖直火蔓延行为中多组分热解气体溢出流场与燃烧补气流场的相互作用与演化规律。.本研究有助于弥补现有固体火蔓延理论在热解气体和气固边界耦合方面的不足，具有重要的理论意义；同时，针对多组分热解气体所建立的火蔓延相关模型以及求解器，将弥补数值模拟方面的不足，进而对森林火灾和建筑火灾等的火蔓延预测提供参考价值。

热解气体是固体火蔓延中固相热解和气相燃烧阶段耦合的关键因素，真实火蔓延过程往往包含多种组分的热解气体，不同热解气体表现出不同的物化特性进而影响火蔓延行为，但现有研究主要针对单一组分的热解气体。本项目的研究目标是基于多组分热解气体，研究典型炭化固体可燃物的火蔓延机理及相关模型。. 本项目执行三年以来，已经圆满完成了既定研究目标，取得了以下研究成果：（1）揭示了典型炭化固体可燃物木材热解生成的多组分气体，以及与半纤维素、纤维素和木质素等固体组分的关联演化；（2）耦合多种热解反应机理与人工智能优化算法，揭示最佳热解动力学参数求解方法；（3）建立了基于多组分热解气体的燃烧模型、辐射模型、烟模型等，及完整的火蔓延求解器multiFireFOAM，细化揭示燃烧行为。. 该项目有助于弥补现有固体火蔓延理论在热解气体和气固边界耦合方面的不足，具有重要的理论意义；同时，针对多组分热解气体所建立的火蔓延相关模型以及求解器，将弥补数值模拟方面的不足，进而对森林火灾和建筑火灾等的火蔓延精确预测提供参考价值。