泡沫铜对密闭管道内合成气爆炸特性影响的实验研究OACSTPCD

In order to investigate the effect of the pore density of copper foam and hydrogen volume fractions(φ)on the in-air-explosive characteristics of premixed syngas,copper foams with pore densities of 15,25 and 40 ppi were fixed in a closed pipe(100 mm× 100 mm× 1000 mm)500 mm from the ignition end.Correspondingly,the premixed syngas-air flame propagates in duct without copper foam was compared.The configuration,tip velocity and overpressure,etc.of the flame were observed by igniting the premixed syngas with equivalence ratio of 1 to the air and a wide range of hydrogen volume fractions(from 10％to 90％).Detailed flame evolution process was visualized by a high-speed camera and the overpressure was recorded by pressure transducer.The results indicates that the copper foam has a significant impact on flame propagation and overpressure-time history.Before the flame reaching the copper foam,its configuration and tip velocity,as well as the overpressure,are only determined by the fuel component,but not the foam,during its formation process to a tulip shape.The pore density and φ affect not only the formation time of tulip flame,but also the appearance of distorted tulip flame.The copper foam could lead to the segmentation of flame front and transform the flame front from laminar to turbulence,resulting in the flame acceleration.This phenomenon becomes more evident with the decreasing of pore density.The presence of copper foam can increase the flame tip speed and overpressure significantly.For the case with a smaller pore density,both the maximum flame tip speed,growth of overpressure and maximum overpressure of premixed syngas-air increase with theφ.