多过程参数的粉尘爆炸泄放动力学特性研究

The mechanism and dynamic characteristics of dust explosion venting based on the multiple process parameters including pressure, flame, particles and venting flow field are important subjects which can supply and improve the existing theory, technology and design methods of dust explosion venting. By using the experimental investigations with high frequency sensor technology and digital image technology, the parameters of explosion overpressure, flame regime and structures, burnt and unburnt particles, and venting flow filed both in confined vessels and vented vessels would be real-time monitored continuously. The distributions of those process parameters in space and with time and the dynamic characteristics would be obtained. The proper physical model of dust explosion venting would be established in order to interpret the special phenomenon during dust explosion venting including secondary explosion, secondary flame, un-expanded jet flame, and so on. The criteria condition of the physical models would be set associating with experimental results and theoretical analysis. This research will provide the theoretical principle for improving the theory, technology and design method of dust explosion venting.

基于压力、火焰、颗粒及泄放流场等多过程参数的粉尘爆炸泄放机理及动力学特性是补充和完善现有可燃粉尘爆炸泄放理论、技术和设计方法的重要课题。本项目拟以实验研究为主要手段，利用高频传感测试技术和光学图像技术，实现密闭容器内粉尘爆炸以及粉尘爆炸泄放过程中压力、火焰形态及前端结构、已燃未燃颗粒及泄放流场的实时监测，获得上述过程参数在时间和空间的变化规律及动力学特性，建立合理的粉尘爆炸泄放物理模型以揭示泄放过程中出现的二次爆炸、二次火焰及欠膨胀射流火焰等特殊现象，并结合理论分析建立泄放物理模型的判定准则。该研究课题的开展，将进一步完善可燃粉尘爆炸泄放理论、技术和设计方法，对安全生产具有重要意义。

已开展的粉尘爆炸泄放设计方法及研究成果已经无法满足日益复杂的粉尘爆炸泄放技术的要求。深入研究基于多参数的粉尘爆炸泄放机理，对完善粉尘爆炸理论及防护技术具有重要意义。本项目以混合低浓度气体的粉尘爆炸体系为研究对象，通过理论及实验方法，系统研究了粉尘爆炸泄放特性，优化了爆炸泄放设计方法。结果表明，可燃气体的添加可导致粉尘最大爆炸压力和爆炸指数明显增大，且爆炸指数的增长率明显高于最大爆炸压力，即可燃气体对粉尘爆炸指数的影响更为显著。根据实验结果建立了由单相体系爆炸参数（PmaxG、PmaxST、KG、KSt）预测两相体系爆炸参数（PmaxH、KH）的模型：.PmaxH=PmaxSt+（PmaxG-PmaxSt）·Φ.KH=KSt+（KG-KSt）·Φ·Φ.结果发现，现有的爆炸泄放设计标准NFPA 68和EN14491对气粉两相泄放的设计结果均偏于保守。提出了关联多个泄放参数包括单相介质最大爆炸压力（PmaxG、PmaxSt）、爆炸指数（KG、KSt）、可燃气体当量比Φ的超压泄放设计方法，经验证证实了泄放设计方法的可靠性和精度。