Two-Dimensional Visualization of Premixed-Charge Flame Structure in an IC Engine - SP-715
Two-Dimensional Visualization of Premixed-Charge Flame Structure in an IC Engine - SP-715
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DOI：
10.4271/870454
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发表时间：
1987-02
期刊：
影响因子：
--
通讯作者：
A. Z. Loye;F. Bracco
中科院分区：
文献类型：
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作者：
A. Z. Loye;F. Bracco
首次用二维空间分辨率研究了预混合装药、火花点火、进气道发动机中的火花核和火焰前缘。最重要的结论是：（1）该发动机中的火焰锋处于反应片区域;（2）随着发动机转速的增加，火焰锋变得更加复杂和混乱，并最终在激光片平面内变得多重连接;（3）在贫油极限附近，火焰锋变得更加扭曲，结果强烈地表明发生了局部熄灭;（4）湍流流场影响了所有被测点火核心，包括小至2 mm的核心和点火后短至100微秒的核心，（5）随着发动机转速的增加，点火核心的畸变和循环变化增大;（6）在1200和2400 rpm之间，火焰片的表面积的估计增加几乎与发动机速度成线性比例，但仅为2-在300至1200 rpm之间观察到火焰片表面积成倍增加。这与燃烧持续时间的相应变化相一致;（7）结果有力地支持了在反应层区中，湍流火焰速度比层流火焰速度的增加主要是由于火焰层表面积的增加;（8）湍流火焰区的厚度随燃烧质量分数和发动机转速的增加而增加。«少
Spark kernels and flame fronts in a premixed-charge, spark-ignition, ported engine were examined for the first time with two-dimensional spatial resolution. The most important conclusions are: (1) the flame fronts in this engine are in the reaction sheet regime; (2) the flame fronts become more convoluted and disrupted as the engine speed is increased and eventually become multiply connected in the plane of the laser sheet; (3) near the lean limit, the flame fronts become more distorted and the results strongly suggest that local extinction is taking place; (4) the turbulent flow field affects all the ignition kernels examined, which included kernels as small as 2 mm and times after ignition as short as 100 microseconds; (5) the distortion and cycle-to-cycle variation in the ignition kernel increase with engine speed; (6) the estimated increase in surface area of the flame sheet scales almost linearly with engine speed between 1200 and 2400 rpm but only a two-fold increase in the surface area of the flame sheet was observed between 300 and 1200 rpm. This agrees well with corresponding variations in combustion duration; (7) the results lend strong support to the theory that in the reaction sheet regime the increase of themore » turbulent flame speed over the laminar flame speed is caused primarily by an increase in the surface area of the flame sheet; (8) the thickness of the turbulent flame zone was found to increase somewhat with both mass fraction burnt and engine speed.« less