狭长地下受限空间火灾蔓延规律及加速突变动力学机理

The special structure of long-narrow confined underground spaces affects the behaviors of fire spread, e.g. the trench effect, the Coanda effect. These effects obviously change the fire spread behaviors, and easily causes the flame acceleration sudden-change. Most researches focused on the fire properties and its suppression effects. However, the interaction mechanisms of hydrodynamic behavior and heat transfer on the acceleration mutation have not been well interpreted yet. In this study, the meso and micro-scale experiment system was performed to explore the Coanda and trench combined effects on the fire acceleration mutation as well as its critical conditions, accompanied with hydrodynamics and heat transfer theories and thermal disaster diagnosis methods. The characteristics of flame flow field distribution and the temperature distribution in gas and solid phase are to be measured using the schlieren and photography system, DPIV and the fine thermocouple, to explore the mechanisms of hydrodynamic and heat transfer behaviors on the acceleration mutation. Furthermore, the acceleration mechanisms are to be revealed, and its prediction model which considers the Coanda and trench combined effects is to be obtained. These research results provide reliable test data and support for the fire prediction, assessments and protection in long-narrow confined underground spaces.

狭长地下受限空间的结构特殊性会对其火灾蔓延规律产生影响，比如巷道效应和Coanda效应（又称壁面吸附效应）。这些动力学行为作用会明显改变狭长地下受限空间的火灾蔓延规律，容易导致火灾蔓延发生加速突变。目前狭长受限空间的火灾研究主要集中在火灾特性及其防治技术效果上，尚没能深入揭示其火灾加速突变内在动力学和传热行为作用机理。本研究拟通过实验研究，将流体动力学和传热理论与热灾害实验诊断技术相结合，研究倾角和巷道效应耦合作用下火灾蔓延规律及其加速突变的内在机理，并建立加速突变理论预测模型。本研究采用纹影摄像、DPIV和精细热电偶等技术，得到不同通道倾角和断面尺寸作用下气相火焰流场结构和气固相温度场变化特性，从微观动力学和传热机制上揭示火灾发生加速突变的内在机理，并建立耦合考虑倾角和巷道效应的火灾加速突变理论预测模型。课题研究可以为狭长地下受限空间火灾演化行为的预测评估及其防治提供理论基础和实验依据。

狭长地下受限空间的结构特殊性会对其火灾蔓延规律产生影响，比如巷道效应和Coanda效应（又称壁面吸附效应）。这些动力学行为作用会明显改变狭长地下受限空间的火灾蔓延规律，容易导致火灾蔓延发生加速突变。目前狭长受限空间的火灾研究主要集中在火灾特性及其防治技术效果上，尚没能深入揭示其火灾加速突变内在动力学和传热行为作用机理。本研究拟通过实验研究，将流体动力学和传热理论与热灾害实验诊断技术相结合，研究倾角和巷道效应耦合作用下火灾蔓延规律及其加速突变的内在机理，并建立加速突变理论预测模型。。本研究采用纹影摄像、DPIV和精细热电偶等技术，得到不同通道倾角和断面尺寸作用下气相火焰流场结构和气固相温度场变化特性，从微观动力学和传热机制上揭示火灾发生加速突变的内在机理，并建立耦合考虑倾角和巷道效应的火灾加速突变理论预测模型。课题研究可以为狭长地下受限空间火.灾演化行为的预测评估及其防治提供理论基础和实验依据。