Modeling and Simultaneous Measurement of Local Concentration of Soot and Aromatic Carbon Concentration and Temperature

采用激光诱导白炽灯（LII）、时间分辨激光诱导白炽灯（TIRE-LII）和干涉激光成像液滴尺寸测量（ILIDS）研究了层流逆流场稳定喷雾火焰中烟尘的形成过程。通过LII和TIRE-LII方法可以得到火焰中烟灰的数量、烟灰体积分数、烟灰粒径和烟灰数密度。二维烟尘体积分数分布采用LII法测量，二维烟尘初级粒径分布采用TIRE-LII法测量。TIRE-LII方法的基本思想是测量烟灰颗粒冷却过程中两个不同时刻的白炽信号，并计算信号强度比。此外，分别通过LII法和TIRE-LII法测量的烟尘体积分数和烟尘粒径计算烟尘数密度。在喷雾燃烧中，火焰的形成受液滴大小的影响，为了使喷雾更加均匀分布，我们采用了振动孔式雾化器来控制喷雾特性。随着平均液滴尺寸的增大，LII烟尘产生的频率增加，在许多情况下，喷雾火焰中烟尘浓度的空间分布呈环形，内腔，火焰外围区域的烟尘初级尺寸大于火焰中心区域的烟尘初级尺寸。相反，火焰中心区域周围的烟炱数密度高于火焰外围区域周围。这说明烟灰主要是在火焰的中心区域周围形成的，烟灰在向外扩散的过程中逐渐长大。同时应用ILIDS和LII技术研究喷雾液滴空间分布与烟尘浓度的关系，了解喷雾火焰中烟尘的形成过程。利用ILIDS方法将离焦图像压缩成线性干涉图，得到液滴特征的空间信息。发现液滴尺寸越大，液滴越接近低燃烧器，即大液滴在获得足够的热量之前不会蒸汽。烟尘浓度的内腔是由于火焰中心区域未燃烧的液滴吸收周围的热量或使其周围富燃料而形成的。少

Laser Induced Incandescence (LII), Time-Resolved Laser Induced Incandescence (TIRE-LII) and Interferometric Laser Imaging Droplet Sizing (ILIDS) were applied to investigate soot formation process in a spray flame stabilized in laminar counter-flow field. Three quantities of soot, soot volume fraction, soot particle sizes, and soot number density in the flame were accessible by LII and TIRE-LII methods. The distribution of two-dimensional soot volume fractions was measured by LII method, and the distribution of two-dimensional soot primary particle sizes was measured by TIRE-LII method. The basic idea of TIRE-LII method is to measure the incandescence signal at two different timing during the cooling of the soot particles and to calculate a signal intensity ratio. In addition, soot number density was calculated from soot volume fraction and soot particle size measured by LII and TIRE-LII methods, respectively. In the spray combustion, the flame formation is affected by the droplet size … More distribution of spray, we control the spray characteristics by the vibratory orifice atomizer. The frequency of LII soot production is increased as the mean droplet size is larger, and in the many cases, spatial distribution of soot concentration in the spray flame were ring-shaped with inner cavity and the soot primary size was larger around the outside region of the flame than around the center region of the flame. To the contrary, the soot number density was higher around the center region of the flame than around the outside region of the flame. This indicates that soot is formed mainly around the center region of a flame and soot grows up as it is conveyed to outside region. ILIDS and LII techniques were simultaneously applied to study the relation between spatial distribution of spray droplet and soot concentration in order to understand soot formation process in the spray flame. ILIDS method was used to get spatial information of the droplet characteristics by compressing defocus image into liner interferogram. It is found that the larger the droplets size is, the nearer the droplets fall to low burner, that is the large droplets don't vapor until they get enough heat. And the inner cavity of soot concentration was resulted from unburned droplets that exist in the center region of the flame due to absorbing the heat around them or making fuel-rich condition around them. Less