变径管道中粉尘爆炸传播实验与模拟

Experiment and Simulation of Dust Explosion Propagation in Tapered Pipelines

为探究粉尘爆炸在变径管道中的传播规律,基于1 m 3粉尘爆炸测试系统,搭建了DN200长直管道和DN200~DN100的变径管道,以玉米淀粉为实验介质,通过实验和FLACS数值模拟相结合的方法,研究了粉尘爆炸在管道中火焰传播速度、超压峰值、火焰传播距离的变化规律.结果表明:火焰传播速度在管道内呈上升趋势,在变径点之后增幅明显变大,缩小管径对火焰传播起加速作用;但超压峰值在管道内呈下降趋势,其在变径后衰减幅度显著升高,缩小管径使超压衰减速率增加;通过数据拟合建立了变径管道引起爆炸腔内超压变化的数学模型;火焰传播距离随浓度增加而变长,相同浓度下渐缩变径管导致火焰传播距离变长.研究结果为除尘系统安全距离确定及阻火隔爆措施的设计提供了参考依据.

In order to investigate the propagation of dust explosion in the tapered pipelines,DN200-long straight pipeline and DN200~DN100 tapered pipeline were built based on 1 m 3 dust explosion chamber testing system.Using corn starch as the testing sample,the flame propagation speed,the peak overpressure in the pipeline and the flame propagation distance were studied by experiment and FLACS numerical simulation.It was found that the flame propagation velocity in the pipeline generally shows an increasing trend,especially after the diameter changing point of the pipe.The reduction of the pipe diameter accelerates the flame propagation.The peak overpressure in the pipeline shows a downward trend,and its attenuation amplitude increases significantly after reducing the diameter.The reduction of the pipe diameter makes the overpressure attenuation rate increased,the mathematical model of the overpressure change in the explosion cavity caused by the variable diameter pipeline is established by data fitting,the flame propagation distance becomes longer as the dust concentration in the chamber increases,and the flame propagation distance becomes longer as the pipe diameter is reduced largely.The research provides reference and guidance for the determination of the safety distance of the dust removal system and the design of fire and explosion prevention measures.