真空腔抑制管道气体爆炸的转捩及控制机理研究

Gas explosion in pipe has a profound influence in a wide range of areas, and does great harm. The traditional suppression explosion methods have the problems of suppression failure and secondary explosion. The each traditional method of suppression explosion has its own characteristics, and plays an important role. However, those methods have the problems, such as the suppression explosion failure and stimulating explosion. Vacuum chamber can attenuate the shock wave and extinguish flame, and it can effectively suppress and interdict gas explosion. However, suppression explosion using vacuum chamber also have the risk of suppression failure and secondary explosion. To explore the failure and transition mechanisms and improve the effectiveness and reliability of suppression explosion, the study designs the experimental system of suppression explosion using vacuum chamber, and also uses the macro-and-micro numerical simulation methods. This study systematically researches the relation among expansion wave, shock wave and flame, and unveils causes and laws that vacuum chamber suppresses explosive flame. In addition, this study analyzes the suppression explosion instability under the critical condition and secondary explosion mechanism that caused by vacuum chamber to elaborate the failure characteristics and transition mechanism of vacuum chamber. The research also optimizes vacuum chamber structure, verifies the stability and reliability of vacuum chamber of multi-sucking mouths, and explores the coupling suppression explosion effect of suppression-explosion dose and vacuum chamber. That results in the best way to decrease the critical volume of vacuum chamber, and the optimal control mechanism and method of the suppress transition phenomenon of vacuum chamber. Finally this study establishes theoretical model and optimal control model of transition, which provides the theoretical base of vacuum chamber suppressing explosion.

管道气体爆炸影响范围广，危害大。其传统的抑爆方法各有特色、发挥了重要作用，但存在抑爆失效甚至激励爆炸的难题。真空腔能够衰减爆炸激波、熄灭火焰，可以有效抑制并阻断瓦斯爆炸，但也有抑爆失效和二次爆炸的风险。为了探明真空腔抑爆失效机理及对应的转捩机制，提高真空腔抑爆的有效性和实用性，本项目将组建真空腔管路抑爆实验系统，并建立真空腔抑爆的宏观和微观数值仿真方法，系统研究真空抽吸膨胀波与爆炸冲击波和火焰的相互关系，揭示真空腔熄灭爆炸火焰的原因和规律；分析真空腔引起的二次爆炸机理及临界条件下的抑爆失稳特性，阐明真空腔的失效特征和转捩机制；优化真空腔结构，探明多吸口真空腔抑爆的稳定性和可靠性，探索真空腔和抑爆剂耦合抑爆效果，得到减小真空腔临界体积的最佳方法，获取真空腔抑爆转捩现象的最优控制机理；构建真空腔抑爆转捩理论模型和抑爆转捩优化控制模型，为真空腔抑爆技术提供理论基础。

管道作为可燃气体介质流通的重要工具，其应用范围和规模在逐渐扩大。管道输送方便快捷，但也会引起严重的事故。真空腔可以衰减爆炸激波、熄灭火焰，抑制管道气体爆炸。为了提高真空腔抑爆的有效性，本项目自行设计制作了真空腔抑爆装置，从理论分析、数值模拟、实验研究、理论建模四个方面，详细分析了真空腔泄爆的作用机理、发展过程和主要影响因素，研究了真空腔焠熄机理、影响因素、耦合抑爆效果，构建了真空腔抑爆效果的理论模型和效果评价模型。.首先利用传热、传质、链式反应和能量衰减理论对有真空腔泄爆环境下的瓦斯爆炸传播规律进行分析阐述。利用详细化学反应机理，研究了真空腔对甲烷链式反应动力学的影响。基于理论和实验分析的结果，建立管道内甲烷/空气预混气体爆炸的物理和数学模型，对安装有真空腔的管道内瓦斯爆炸进行了数值模拟研究。从爆炸火焰传播、爆炸超压、爆炸温度以及爆炸产物浓度四个方面，对有腔管道和无腔管道瓦斯爆炸进行对比分析。通过构造不同的真空腔实验系统，研究了真空腔体积、弱面板破裂时机、真空腔真空度等关键参数对真空腔抑爆效果的影响。真空腔抑爆存在一临界体积，当真空腔体积大于临界体积时，真空腔就有抑爆效果；真空腔弱面板破裂时机很重要，如果弱面板破裂时，火焰已经远离真空腔，则真空腔没有抑爆效果，所以真空腔有效的关键是，真空腔弱面板能及时破裂；真空腔并不是只有在完全真空下才起作用，当真空腔达到一定真空度后，就有明显的抑爆效果。.利用遗传算法优化的神经网络，根据真空腔抑爆特点，建立了神经网络的基本结构，确定了神经网络的输入输出参数和计算方法，对真空腔实验数据进行了分析，找到了真空腔抑爆效果影响因素指标与真空腔抑爆效果评价指标之间的非线性关系，并通过控制变量法，定量分析了其相互影响规律，得到了评价真空腔的抑爆效果的拟合公式，对真空腔抑爆效果评价具有指导意义。