Modelling of soot formation in a heavy-duty diesel engine with conditional moment closure
Modelling of soot formation in a heavy-duty diesel engine with conditional moment closure
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DOI：
10.1016/j.fuel.2013.09.041
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发表时间：
2014-01
期刊：
影响因子：
7.4
通讯作者：
M. Bolla;Daniele Farrace;Y. Wright;K. Boulouchos
中科院分区：
文献类型：
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作者：
M. Bolla;Daniele Farrace;Y. Wright;K. Boulouchos
本研究首次将多维条件矩闭燃烧与双方程烟尘模型应用于柴油机缸内烟尘的演化研究。用光学可及重型柴油机的5个高保真参考案例验证了模型的预测；其中包括两种高温工况和两种不同注入时间的低温工况，以及一种分离注入策略的低温工况。通过非反应性燃料蒸汽分布、表观放热率（AHRR）、定量缸内烟尘质量和自然亮度的时间演变，将模拟结果与实验数据进行了比较。该模型能够再现所有五种情况下烟尘质量的半定量趋势。特别是在低温条件下，烟灰形成和氧化的演变被很好地捕获。为了保证计算得到的三维烟尘与实测的二维烟尘自然亮度图像的一致性，提出了对三维烟尘进行视距变换的方法。用这种方法观察到与辐射吸附有关的附加效应。在定性上很好地再现了视距煤烟自然光度的演变。总体而言，研究结果表明，在CMC框架下实现的双方程烟尘模型对于预测不同燃烧模式下柴油机缸内烟尘的时间演变非常有希望。
This study presents the first application of a multidimensional conditional moment closure (CMC) combustion with a two-equation soot model to study the evolution of in-cylinder soot in diesel engines. Five high-fidelity reference cases from an optically accessible heavy-duty diesel engine were used to validate the model predictions; these include two high-temperature cases and two low-temperature cases with two different injection timings and one low-temperature case with a split injection strategy. Simulation results have been compared with experimental data by means of non-reactive fuel vapour distribution, apparent heat release rates (AHRR), temporal evolutions of quantitative in-cylinder soot mass and natural luminosity. The model was capable to reproduce semi-quantitative trends of soot mass for all five cases. In particular for low-temperature conditions the evolution of soot formation and oxidation is very well captured. A line-of-sight transformation of the computed 3D soot is proposed to ensure a consistent comparison with the measured 2D soot natural luminosity images. With this methodology additional effects related to radiation adsorption were observed. Evolutions of line-of-sight soot natural luminosity were qualitatively very well reproduced. Overall the findings suggest that the presented two-equation soot model implemented in the CMC framework is a highly promising candidate for predicting time evolutions of in-cylinder soot for diesel engines operating in different combustion modes.