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This study presents a new model to simulate the electric behaviour of one-dimensional ionised flames and to predict the electric currents in these flames. The model utilises Poisson’s equation to compute the electric potential. A multi-component diffusion model, including the influence of an electric field, is used to model the diffusion of neutral and charged species. The model is incorporated into the existing CHEM1D flame simulation software. A comparison between the computed electric currents and experimental values from the literature shows good qualitative agreement for the voltage–current characteristic. Physical phenomena, such as saturation and the diodic effect, are captured by the model. The dependence of the saturation current on the equivalence ratio is also captured well for equivalence ratios between 0.6 and 1.2. Simulations show a clear relation between the saturation current and the total number of charged particles created. The model shows that the potential at which the electric field saturates is strongly dependent on the recombination rate and the diffusivity of the charged particles. The onset of saturation occurs because most created charged particles are withdrawn from the flame and because the electric field effects start dominating over mass based diffusion. It is shown that this knowledge can be used to optimise ionisation chemistry mechanisms. It is shown numerically that the so-called diodic effect is caused primarily by the distance the heavier cations have to travel to the cathode. 相似文献
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Marco Ferrarotti Zhiyi Li Alessandro Parente 《Proceedings of the Combustion Institute》2019,37(4):4531-4538
The present work shows an in-depth analysis about the role of mixing models on the simulation of MILD combustion using a finite-rate combustion model, the Partially Stirred Reactor approach (PaSR). Different approaches of increasing complexity are compared: a simple model based on a fraction of the integral time scale, a fractal-based mixing model and a dynamic mixing model based on the resolution of transport equations for scalar variance and dissipation rate. The approach is validated using detailed experimental data from flames stabilized on the Adelaide Jet-in-Hot Co-flow (JHC) burner at different fuel-jet Reynolds numbers (5k, 10k and 20k) and different co-flow oxygen dilution levels (3%, 6% and 9%). The results indicate the major role of mixing models to correctly handle turbulence/chemistry interactions and clearly indicate the superior performances of the dynamic mixing model over the other tested approaches. 相似文献
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预燃室是一种高效、低NOx排放很有发展前途的洁净煤燃烧技术。但是,目前由于其体积过大,使它在实际应用中受到限制。本文叙述的逆向复式射流预燃室燃烧器结构简单、体积小、燃烧效率高、煤种适应性强,可望成为符合洁净煤技术要求的高效、低NOx主燃烧器。 相似文献
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煤的模型化合物混合燃料气流床气化中N的迁移研究 总被引:2,自引:0,他引:2
将吡啶配入柴油中模拟煤中氮的存在形式,考察了混合燃料在四喷嘴对置式气化炉中,轴径向位置HCN、NH3、NO和N2的浓度分布。结果表明:氮污染物(HCN、NH3、NO)在喷嘴平面处即产生且浓度最高,远离喷嘴平面时其浓度大幅降低,N2也裂解参与了气化反应,且出口浓度N2>HCN>NH3>NO;氧燃料比增高,NO、N2增加;氧燃料比1.3时HCN、NH3浓度最高,0.9和1.7时浓度较低;流场的分布使靠近出口处径向浓度基本一致,而上部各平面位置浓度靠近炉壁处最低;水汽的加入使HCN、NH3浓度增高而NO浓度降低。 相似文献
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介绍了基于半导体激光器作光源的吸收光谱测温技术研究和开发集成的系统,利用H2O在1.4μm附近的吸收线对的线强比值来反演温度.介绍了该系统在实验室管式高温上的标定和开放炉管的测量验证,结果显示各设置温度下测量温度波动平均在50 K左右.之后在CH4/空气预混平焰炉上进行进一步验证,发现在吸收线7153.7 cm-1长波一侧出现了HITRAN08中未给出的几条H2O吸收和该吸收线重叠.HITEMP中在这些波长上有对应的吸收线给出,但对另一条选用的吸收7154.354 cm-1,给出的可对应吸收线中心频率和测量不一致.根据实验测量结果和HITRAN/HIlTEMP的对比,对选择吸收线对的位置和线强等参数继续采用实验室标定结果,并引入HlTEMP中给出的这些高温下表现出来的吸收线参数,在平焰炉不同当量比状态下做了测量对比. 相似文献