Critical Condition for the Combustion Rate of a Carbon Particle to be Activated: Theory and Experimental Comparisons
Critical Condition for the Combustion Rate of a Carbon Particle to be Activated: Theory and Experimental Comparisons
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碳颗粒被激活的燃烧速率的临界条件：理论与实验比较
DOI：
10.1080/00102202.2018.1511543
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发表时间：
2018
影响因子：
1.9
通讯作者：
A. Makino
中科院分区：
文献类型：
--
作者：
A. Makino
本文从固体燃料颗粒活化的角度出发，得到了颗粒燃烧速率的临界条件。使用已取得的渐近性，重点是在平台阶段的粒子质量的时间变化，以及粒子温度。研究表明，该临界条件与热损失密切相关，存在一个由燃烧速率、氧质量分数和压比组成的综合参数，它只与环境温度有关。适当的和/或有用的临界条件已被进一步审查，通过使用文献中的实验数据，据报道，在静态环境中燃烧。用综合参数的Arrhenius图进行了实验比较，结果表明，由临界条件分隔的上半区对应于表面反应被激活的颗粒燃烧区。所用的实验数据是从半无烟煤到低阶煤焦，以及石油焦，包括烟灰。已经证明了相当程度的一致性，表明可以在扩散控制制度中燃烧的较大颗粒位于上半区，并且未能在表面反应中被激活的较小颗粒位于临界条件以下。借助于这一临界条件，人们甚至建议，通过检查在准稳态下测量的燃烧速率，可以容易地预测燃烧过程中的颗粒活化。最后，再次证实，颗粒尺寸的减小，这也对颗粒失活产生影响，并不一定有利于颗粒燃烧。
ABSTRACT Relevant to the activation of solid fuel particle, critical condition for the combustion rate has been obtained, above which particle combustion can successfully be accomplished. Use has been made of the asymptotics, with focusing on the temporal variation of the particle mass in the plateau stage, as well as that of the particle temperature. It has been confirmed that this critical condition is closely related to the heat loss, and that there exists a comprehensive parameter, consisting of the combustion rate, oxygen mass-fraction, and pressure ratio, which only depends on the ambient temperature. Appropriateness and/or usefulness of this critical condition has further been examined, by use of such experimental data in the literature as are reported to burn in the quiescent environment. Arrhenius plot of the comprehensive parameter has been used in experimental comparisons, in which it is indicated that the upper half region separated by the critical condition corresponds to that for the particle combustion with surface reactions activated. Experimental data used are those from semi-anthracite to low-rank coal char, as well as petroleum coke, including soot. A fair degree of agreement has been demonstrated, indicating that the larger particles that can burn in the diffusion controlled regime locate in the upper half region, and that the smaller ones that have failed to be activated in the surface reactions locate below the critical condition. By virtue of this critical condition, it is even suggested that prediction for the particle activation in the course of combustion can easily be made, by examining combustion rate measured in the quasi-steady state. Finally, it is confirmed again that the reduction in particle size, which also exerts influences on particle deactivation, does not necessarily favor the particle combustion.