Characterization of Turbulent Combustion using Advanced Laser Diagnostics

湍流燃烧几乎发生在所有与燃烧相关的应用中，包括燃气轮机、锅炉、熔炉、发动机、爆炸和火灾。深入了解湍流燃烧的基本现象，对于发展先进的燃烧技术以实现低排放和高能效是至关重要的。由于复杂的湍流-化学相互作用，预混湍流燃烧引起了实验者、模型师和理论家的极大关注。这种强烈的相互作用给测量湍流燃烧速度带来了最大的挑战，湍流燃烧速度被定义为进入火焰前沿的气体速度。本项目旨在通过使用空间(x-，y-，z-)和时间(T)分辨率4D激光分析来测量预混湍流火焰的燃烧速度和火焰结构，从而准确地表征预混湍流火焰。出于上述目的，该项目涉及开发先进的激光诊断技术，例如粒子图像测速PIV，作为表征气体湍流的一种实用方法。它包括在浓度非常有限的气雾剂中播撒含有小颗粒橄榄油的气体，激光形成一张照亮播撒颗粒的光片。用高速高分辨率数码相机记录散射光，提取速度场。同时，将摆动的激光片结合在一起，得到三维湍流火焰结构，可以定量表征火焰表面积、燃烧气体体积、反应进程变量和火焰表面密度。这项研究的成果将是一种独特的爆炸火焰传播的高速摄影技术。这将大大加深对预混湍流火焰的理解，并表征新开发的燃料的湍流燃烧速度，确保其在全球能源转型背景下的成功应用。

Turbulent combustion takes place in nearly all combustion-related applications, including gas turbines, boilers, furnaces, engines, explosions and fires. A thorough understanding of the basic phenomena of turbulent combustion is essential to develop advanced combustion technologies to achieve low exhaust emissions and high energy efficiency. Premixed turbulent combustion attracts the most attention from experimentalists, modellers, and theoreticians, due to a complex turbulence-chemistry interaction. This strong interaction brings the greatest challenge to measure a turbulent burning velocity that is defined as the gas velocity into the flame front. This project seeks to accurately characterize the premixed turbulent flame by measuring the burning velocity and the flame structure using spatially (x-, y-, z-) and temporally (t) resolved 4D laser analysis. For the above purposes, this project involves developing advance laser diagnostics, e.g. particle image velocimetry PIV, as a practical way of characterising gaseous turbulence. It involves seeding the gas with small particles of olive oil in an aerosol of very limited concentration and a laser beam is formed into a light sheet illuminating seeding particles. The scattered light is recorded using a high speed and high resolution digital camera for extracting the velocity field. Meanwhile, swinging laser sheets will be incorporated to obtain the three-dimensional turbulent flame structure which allows quantitatively characterization on flame surface area, burned gas volume, reaction progress variable and flame surface density. The outcome of the research will be a unique technique of high speed photography of explosive flame propagation. This will greatly enhance the understanding of premixed turbulent flame, as well as characterize the turbulent burning velocity of newly developed fuels and ensure their successful application in the context of the global energy transition.