Critical condition relevant to the extinction of a carbon particle in the course of combustion.
Critical condition relevant to the extinction of a carbon particle in the course of combustion.
复制标题
与燃烧过程中碳颗粒消失相关的临界条件。
DOI：
10.1016/j.proci.2020.06.339
复制
发表时间：
2020
期刊：
影响因子：
--
通讯作者：
H.
中科院分区：
文献类型：
--
作者：
Makino;A. and Sano;H.
为了考察碳颗粒在燃烧过程中的消光情况，尝试得到了它的临界条件。尽管已经得到了临界条件的下限和上限，但主要关注的是在颗粒燃烧结束时可能发生的下限内的颗粒消光。通过对颗粒温度随时间变化的渐近分析，得到了颗粒直径极限随压力比、氧气质量分数、环境温度和/或辐射热流密度的变化关系的解析表达式。从解析解中还得到了近似表达式。结果表明，该近似表达式能较好地表示极限。此外，还利用了由颗粒直径和压强比组成的综合参数的Arrhenius曲线图，以确定颗粒持续燃烧的区域，这些区域紧邻颗粒消光区域。还利用文献中的实验数据进行了比较，就趋势和近似大小而言，呈现出相当程度的一致性。已经证实，该公式抓住了本质特征，颗粒尺寸的减小并不一定有利于颗粒的燃烧，当颗粒直径减小到临界值时，颗粒会发生消光。
In order to examine extinction of carbon particle in the course of combustion, an attempt has been made to obtain its critical condition. Main concern has been put on the particle extinction in the lower limit that can occur at the end of the particle combustion although not only the lower limit but also the upper limit of the critical conditions has been obtained. By conducting asymptotics, with focusing on the temporal variation of the particle temperature, an analytical expression has been obtained for the limit of the particle diameter, as functions of the pressure ratio, oxygen mass-fraction, ambient temperature, and/or radiative heat flux. An approximate expression is also obtained from the analytical solution. It is found that the approximate expression can fairly represent the limits. In addition, use has been made of the Arrhenius plot of a comprehensive parameter, consisting of the particle diameter and pressure ratio, in order to identify regions for the particle combustion sustained, which are next to those for the particle extinction. Comparisons have also been conducted by use of experimental data in the literature, with presenting a fair degree of agreement, as far as the trend and approximate magnitude are concerned. It has been confirmed that the formulation has captured the essential feature, that the reduction in particle size does not necessarily favor the particle combustion, and that the particle extinction can occur when the particle diameter is reduced to the critical value.