Research On The Effect Of Wire Mesh On Typical Dust Explosion Characteristics In Ducts

Due to its remarkable suppression effect and low cost,wire mesh has become the main fire-stopping element material for explosion disasters.The flameless relief device is the main device for safe pressure relief of indoor powder-related equipment,and the wire mesh is an important part of its fire arresting element,which has a significant impact on the suppression of dust explosion flames and overpressure relief.However,the existing research results mainly focus on the flame suppression of gas explosion by the fire arresting element of the flameless relief device,and there are few studies on the suppression of dust explosion.The pressure relief efficiency and flame suppression performance of the devices are uneven,which restricts the effective prevention and control of dust explosion accidents and the sustainable development of the explosion-proof industry.In this regard,based on the self-designed experimental device,using low-density polyethylene dust(Low-density polyethylene,LDPE)as the medium,the influence of the characteristics of the wire mesh and the dust characteristics on the flame propagation and overpressure distribution of the pipeline dust explosion was discussed.The content is as follows:(1)Based on the minimum ignition energy test equipment,a test device for the influence of wire mesh on dust explosions was independently designed,and an adjustable wire mesh component structure was added to realize the relationship between the number of wire mesh,the number of layers and the distance between them and the dust particle size,Effective measurement of dust explosion flame velocity,shape and overpressure distribution under the synergistic conditions of dust concentration and other factors.And through the experiment,the dust cloud concentration is 1040 g/m~3,and the D50 is 122.1μm as the dust parameters of the follow-up experiment.(2)The influence of mesh size of wire mesh and dust characteristics on the dust explosion characteristics of LDPE was studied.Under the condition of specific dust cloud concentration,this study found that the effect of single-layer wire mesh on the explosion flame propagation is related to its mesh number.When the mesh number is less than or equal to 40,it can promote the flame propagation;when the mesh number is greater than or equal to 60,the flame propagation speed slows down,and in most cases the wire mesh can effectively quench the flame.In addition,increasing the mesh number of the wire mesh can increase the peak value of the internal overpressure of the equipment and reduce the peak value of the external overpressure,thereby slowing down the spread of overpressure.(3)The effect of the synergy between the number of wire mesh layers and dust characteristics on the dust explosion characteristics of LDPE was studied.In the single-layer 20-mesh wire mesh,the explosion of dust cloud with higher concentration is promoted,while the explosion of dust cloud with smaller particle size is suppressed.The increase in the number of layers of wire mesh can enhance the suppression effect of the explosion flame.Except that part of the lower concentration under the2-layer wire mesh and part of the smaller particle size dust cloud explosion flame under the 3-layer wire mesh can pass through the wire mesh,the flames are completely suppressed in the rest of the cases.However,the increase in the number of layers of wire mesh reduces the pressure relief efficiency to a certain extent,resulting in an increase in the explosion overpressure in the lower part of the wire mesh and a decrease in the upper overpressure of the wire mesh.(4)The influence of wire mesh position and dust characteristics on the dust explosion characteristics of LDPE was studied.The results show that as the distance between the wire mesh and the ignition source increases,the average flame propagation velocity and the explosion overpressure inside the mesh first increase and then decrease.