基于自适应简化反应机理的爆燃转爆轰的数值模拟

According to the requirement the prevention and control of the gas explosion disasters, this project develop large-scale numerical simulation of deflagration to detonation transition (DDT) based on adaptive reduction reaction mechanism. The specific research work carried out as follows:(1)the method that can simplify the reaction mechanism is investigated, and a reduction reaction model that can describe different stages from ignition, flame acceleration to DDT is established;(2)governing equations considering chemical reaction, thermal conduction and viscosity, including fluid dynamics equations, state equation and mass fraction equation are built, and conservative high accuracy numerical schemes is constructed, and high resolution code that can simulate on the whole process of DDT by using the adaptive reduction reaction mechanism; (3)effect of the concentration on flame acceleration and DDT, and concentration limit to DDT; DDT and the inherent relationship between of reaction mechanisms of self-ignition and onset of detonation under different initial pressure; influence of the wall heat exchange and the wall-destructed reaction on the ignition, flame acceleration and transition to detonation. Investigations on this project can not only overcome the deficiency of single step reaction model and the detailed reaction mechanism leading to solve dilemma of large-scale computing low efficiency, but also improve the theory of combustion and detonation, and provide a scientific basis for prevention of disasters resulting from gas explosion.

本项目针对气体爆炸灾害预防和防治的要求，开展基于自适应简化反应机理的爆燃转爆轰的大规模数值模拟。具体开展如下研究工作: （1）研究能够准确地简化反应机理的方法，建立能够描述点火、火焰加速及爆燃转爆轰全过程的简化反应模型；（2）建立考虑粘性扩散和热传导的化学反应流体动力学的控制方程组，构造守恒型高精度数值格式，开发具有自适应简化反应机理的爆燃转爆轰的计算程序；（3）研究浓度对点火、火焰加速和爆燃向爆轰转变的影响规律，以及爆燃转爆轰发生的浓度极限；研究不同初始压力、温度下爆燃转爆轰机理以及自点火化学反应机理与爆燃转爆轰形成之间的内在关联；研究壁面热交换效应和壁面约束作用对点火、火焰加速和爆燃到爆轰转变机理的影响。本项目的研究不仅能够克服单步反应模型的不足，解决详细反应机理导致大规模计算效率低的困境，而且可以完善气体燃烧与爆轰理论，为气体爆炸灾害的预防和防治提供重要的科学依据。

本项目针对气体爆炸灾害预防和防治的要求，开发了能够自适应简化反应机理，并准确地计算爆燃转爆轰全过程的高精度并行程序，解决了目前简单反应模型无法准确描述爆燃转爆轰全过程的不足，克服了由详细反应带来的庞大计算规模的困境，将在爆燃转爆轰的基础研究以及爆炸灾害领域具有重要的应用前景。运用程序研究了微、宏观尺度下爆燃到爆轰的转变模式，给出了爆轰的形成机制，以及二次或多次爆炸的诱发机理，为日益突出的气体爆炸灾害的预防、防治设计提供理论依据。研究了不同环境下爆燃转爆轰，给出了初始温度、压力对爆燃转爆轰的影响规律。研究了边界热损失对爆燃转爆轰的影响，发现了热损失导致火焰加速率减小和爆燃转爆轰距离缩短。进一步研究了爆轰传播不稳定性，发现了自持胞格爆轰是传播不稳定和横向不稳定耦合的结果，揭示了自由空间中的爆轰不稳定性的本质。