基于成像的RP-3煤油在激波管内自点火过程研究

A Study of RP-3 Autoignition in Shock Tube Based on Imaging

关键词:  RP-3煤油  激波管  纹影  火焰

Key words:  RP-3 kerosene  Shock tube  Schlieren  Flame

摘要:

为深入直观了解RP-3煤油在激波管内的自点火及燃烧过程，利用高分辨率纹影系统和高速摄像机对反射激波后点火燃烧过程进行拍摄，获取了丰富的光学图像。纹影图像显示得益于低压段内高比例氩气作为稀释气体，入射及反射激波均无分叉，为正激波结构，点火燃烧后对密度造成较大影响，流场中出现明显褶皱。针对燃烧过程的高速摄影图像显示激波后燃烧区域基本分为两部分，反射激波后小粒径雾化煤油完全燃烧呈现明亮的蓝色火焰，由于氧气的大量消耗随后将造成煤油液滴间的燃烧出现竞争关系，无法充分燃烧，出现分散的黄色火焰区，后期部分液滴由于贫氧及温度下降造成燃烧不充分而析出碳粒。

Abstract:

For deeply and intuitively understanding autoignition and combustion process of RP-3 kerosene in shock tube，high resolution schlieren system and high speed camera were used to take pictures of ignition and combustion process after reflected shock wave，and plenty of optical images were obtained. Schlieren images show that incident and reflected shock wave are both normal shock wave without bifurcation for high ratio argon as diluent gas in low pressure section. Density was strongly affected by ignition and combustion，and wrinkles presented obviously in flowfield. High speed images show that combustion zone basically can be divided into two parts. Atomized kerosene with small droplet size will present light blue flame for perfect combustion after reflected shock wave and oxygen will be largely consumed. Subsequently combustion competition will arise among kerosene droplets and cause insufficient combusiton. Therefore，discrete yellow flame zones present and carbon particles will be produced as the results of inefficient combustion of droplets and decrease of temperature.