透过燃烧图像对汽油机湍流火焰分形特性的试验研究和模拟

摘要

Flame structure of turbulent premixed combustion for gasoline engine has the feature of self-similarity of fractal geometry. Based on the theory about fractal geometry, a turbulent combustion model, called as fractal combus-tion model, is used to simulate engine combustion process. Experimental system in this paper includes an optical en-gine and a high-speed digital CCD camera. Images of turbulent premixed combustion flame are obtained. By process-ing in-cylinder turbulent flame images, some parameters like fractal dimension, flame surface area and turbulent flame velocity are acquired. Simulated results have a good agreement with the experimental results. The study shows that the fractal combustion model is an effective and accurate method to simulate engine working process.%汽油机湍流预混燃烧的火焰结构具有分形几何的自相似性.利用基于分形理论的燃烧模型对发动机的燃烧过程进行了模拟计算,并将计算结果与试验数据进行了对比.试验采用自行设计的以光学发动机和高速摄像机为核心的系统,通过对拍摄到的湍流火焰照片经过图像处理来获取火焰的分形维数、火焰面积、湍流火焰速度等特性参数.研究结果表明:试验结果和模型计算值吻合得较好,分形燃烧模型是一种有效的模拟发动机工作过程的手段,具有良好的预测精度.