Influence of water mist on propagation and suppression of laminar premixed flame
Influence of water mist on propagation and suppression of laminar premixed flame
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DOI：
10.1080/13647830.2017.1422543
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发表时间：
2018-01
影响因子：
1.3
通讯作者：
N. S. Belyakov;V. Babushok;S. Minaev
中科院分区：
文献类型：
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作者：
N. S. Belyakov;V. Babushok;S. Minaev
采用一维近似方法研究了含微水滴的预混气体的燃烧过程。分析了燃烧速度和燃烧极限对初始条件和液滴性质的依赖关系。研究了液滴大小和加液浓度对喷雾效果的影响。结果表明，液滴直径越小，降低火焰速度越有效。对于在反应区内蒸发的液滴，燃烧速度与液滴大小无关，仅取决于添加液体的浓度。随着液滴直径的进一步增大，液滴通过反应区，燃烧产物中的汽化完成。结果表明，对于一定尺寸以上的液滴，存在两种稳定的滞后型过渡火焰传播模式。转变的临界条件是由于液滴汽化通过反应区，在火焰前沿出现最大温度和温度梯度，并伴随着从反应区到产物的热损失。临界条件类似于经典火焰可燃极限的临界条件，具有火焰传播的热机理。临界转折点的燃烧速度和燃烧温度的最大降幅与Zel‘dovich和Spalding的经典可燃极限理论的预测相一致。对有细水雾时火焰传播的定常模式的稳定性分析表明，假设的模型框架中没有振荡过程。
The combustion of premixed gas mixtures containing micro droplets of water was studied using one-dimensional approximation. The dependencies of the burning velocity and flammability limits on the initial conditions and on the properties of liquid droplets were analyzed. Effects of droplet size and concentration of added liquid were studied. It was demonstrated that the droplets with smaller diameters are more effective in reducing the flame velocity. For droplets vaporizing in the reaction zone, the burning velocity is independent of droplet size, and it depends only on the concentration of added liquid. With further increase of the droplet diameter the droplets are passing through the reaction zone with completion of vaporization in the combustion products. It was demonstrated that for droplets above a certain size there are two stable stationary modes of flame propagation with transition of hysteresis type. The critical conditions of the transition are due to the appearance of the temperature maximum at the flame front and the temperature gradient with heat losses from the reaction zone to the products, as a result of droplet vaporization passing through the reaction zone. The critical conditions are similar to the critical conditions of the classical flammability limits of flame with the thermal mechanism of flame propagation. The maximum decrease in the burning velocity and decrease in the combustion temperature at the critical turning point corresponds to predictions of the classical theories of flammability limits of Zel'dovich and Spalding. The stability analysis of stationary modes of flame propagation in the presence of water mist showed the lack of oscillatory processes in the frames of the assumed model.