当大量的可燃性粉尘悬浮在有限空间中，若存在点火源则会引发粉尘爆炸事故。粉尘爆炸事故属于常见的事故类型，其破坏力强、危害大。因此，粉尘爆炸防护技术一直是研究热点。无焰泄爆技术作为可燃粉尘爆燃防控的措施之一，在有效降低粉尘爆炸危险性的同时也具有一定的经济性。但由于粉尘爆燃过程的复杂性，有关无焰泄爆技术的研究多为宏观分析，无焰泄爆技术的机理的研究还需深入。基于此，以玉米淀粉粉尘作为研究性粉尘，金属丝网作为阻火材料，自主搭建粉尘泄爆与无焰泄爆实验平台，开展金属丝网对玉米淀粉粉尘泄爆火焰传播的影响研究，揭示粉尘泄爆火焰特性和无焰泄爆机理，为工业生产过程中的无焰泄爆技术提供指导。

基于自主搭建的粉尘泄爆与无焰泄爆实验平台，本文通过探究由实验所获取火焰图像、爆炸压力以及火焰温度等基础数据，对不同开启压力条件下的粉尘泄爆火焰特性与金属丝网抑制粉尘泄爆火焰传播的过程进行分析，最后对无焰泄爆机理进行研究。研究结果表明：粉尘泄爆火焰在传播过程中火焰形态演化过程为锥形射流火焰→湍流膨胀火焰→弱湍流火焰，开启压力的增加会使得锥形射流火焰形态的维持时间变短。安装金属丝网后，火焰形态演化过程并未改变，但随着安装金属丝网层数或目数的增加锥形射流火焰的维持时间变短。粉尘泄爆火焰在传播过程中，爆炸反应容器内部会出现明显的压力振荡现象。安装金属丝网后，无焰泄爆装置内部的压力振荡强度会被抑制。此外，研究发现压力振荡现象会增强粉尘爆燃火焰的火焰不稳定性，对燃烧反应起到促进作用，进而影响金属丝网的阻火效果。同时，在压力振荡的影响下火焰传播表现出波动振荡的变化特征。

通过对粉尘爆炸泄压火焰抑制机理的研究，将其总结如下：粉尘泄爆火焰传播与阻火结构接触前，装置的抑爆行为表现为对爆炸压力波的抑制以及降低压力振荡对火焰不稳定性的促进作用；当粉尘爆燃火焰与阻火结构接触后，装置则是以淬熄异相燃烧的火焰为主。无焰泄爆机理的核心是对爆炸压力波的抑制以及对异相燃烧火焰的淬熄。

When a large amount of combustible dust is suspended in a confined space, the presence of an ignition source can lead to a dust explosion. Dust explosion is a common type of accident which has occurred in recent years. It is hazardous and has destructive power. Therefore, dust explosion protection technology has been a hot issue for researchers. Flameless venting technology, which is taken as one of the measures to prevent and control the explosion of combustible dust, can effectively reduce the risk of dust explosion, and it also has a certain economic efficiency. However, due to the complexity of the dust deflagration process, the research on flameless venting technology is mostly macroscopically investigated. The research about the mechanism of flameless venting technology needs to be further analyzed. For the purpose of analyzing the characteristic of vented flame, revealing the mechanism of flameless venting and providing guidance for flameless venting technology, an experimental system for dust explosion venting and flameless venting is established. In this experiment, the corn starch dust is the research dust and wire mesh is the fire-resistant material.

Based on the self-established experimental system, the data of flame image, the data of explosion overpressure and the data of flame temperature were obtained. Then, the characteristic of vented flame under different working condition is analyzed, the fire-resistant process of wire mesh is studied and the mechanism of flameless venting is revealed. The results show that the flame shape evolution process of vented flame is conical jet flame → turbulent expansion flame → weak turbulent flame. When the static activation overpressure is elevated, the duration time of conical jet flame will decrease. Meanwhile, the flame shape process doesn’t change when the wire mesh was installed. The duration time of conical jet flame will also decrease when the number of mesh or layers of wire mesh increases. During the propagation of the vented flame, overpressure oscillation will appear in the vent duct. When the wire mesh is installed, the overpressure oscillation inside the flameless venting device is suppressed. In addition, the overpressure oscillation will enhance the instability of flame, promote the combustion reaction and then influence the fire-resistant process of wire mesh. Meanwhile, under the influence of overpressure oscillation, the flame propagation shows the characteristic of fluctuation.

Through the study of the flameless venting mechanism, it can be summarized as follows: before the vented flame contacts with the fire-resistant structure, the explosion suppression behaviours of the flameless venting device are characterized by the suppression of pressure wave and the reduction of flame instability caused by overpressure oscillation; When the vented flame contacts with the wire mesh, the device mainly quenches the heterogeneous combustion flame. The keys of flame venting mechanism are the suppression of explosion shock wave and the quenching of heterogeneous combustion flame.

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