基于IGCC的合成气预混湍流燃烧特性基础研究

Turbulent combustion is the key process in converting chemical energy to thermal energy in the practical devices, such as internal combustion engines, gas turbine and jet engines. Turbulent combustion involves multiple processes of vastly different time and length scales. Among them, fluid dynamics and chemical reactions play the first-order controlling role. Turbulence and chemistry are coupled intimately, which is manifested by complex convex and concave flame front structures of turbulent flames. Turbulence-chemistry interaction is a crucial issue for the understanding of the turbulent combustion and construction of turbulent combustion model. However, it is still far from understanding...IGCC is the most promising clean energy technology due to its superior advantages of fuel diversity and low emissions. IGCC has special importance for China which has plenty reserve of coal and high dependency on imported oil. The IGCC plants will allow the gasification of wide range of liquid and solid fuel or waste to convert into syngas mixtures that can be used in a gas turbine to generate electricity. The syngas combustion in gas turbine is the key technology for IGCC. The main compositions of syngas are CO and H2. Hydrogen possesses unique thermal and transport properties. The existence of hydrogen in the syngas will lead to much different turbulence-chemistry interaction and flame-vortex interaction for syngas turbulent combustion compared to that of hydrocarbons, which may result in the flame instability, combustion oscillation and flashback problems for the state-of-art premixed gas turbine combustor, which needs further study in details...Fundamental study on syngas turbulent premixed combustion as a basis for IGCC is proposed using the advanced experimental facilities of Xi’an Jiaotong University. It is partially based on the applicant’s experience and outstanding achievement on high pressure turbulent premixed combustion and combustion laser diagnostics technique as a JSPS research fellow. And it is mainly based on the National Natural Science Foundation project: Fundamental study of flame characteristics and chemical kinetics reaction mechanism of syngas. The experimental study on turbulence-chemistry interaction of syngas turbulent premixed flames, flame instability and flashback mechanism of syngas swirl-stabilized flames, flame propagation characteristics of laminar/turbulent premixed syngas flames at high pressure will be conducted. The effects of pressure, hydrogen existence and syngas composition variation on the mechanism of syngas turbulent premixed flames and flame dynamics of swirl-stabilized flames will be studied with the combined PIV/PLIF technique. The syngas turbulent combustion model will be developed based on the experimental results. The study has an important academical value and can provide the experimental and theoretical guidance to the independent research and development of gas turbine fueled with syngas for IGCC plants.

本项目在青年基金项目“合成气火焰基础特性和化学反应动力学机理研究”的基础上，结合申请人在日本东北大学研究期间高压预混湍流燃烧和燃烧激光诊断的研究经历和成果，利用西安交通大学燃烧基础研究先进实验平台，系统开展合成气预混湍流燃烧的基础研究。包括湍流尺度与合成气化学反应尺度耦合作用机理、合成气旋流火焰稳定性与回火机理、高压下合成气预混层流/湍流火焰传播特性的基础研究。利用PIV/PLIF激光测量技术，定量研究合成气预混湍流燃烧和旋流稳燃燃烧火焰动力学规律和机理。本项目系统性的基础研究工作将揭示湍流尺度与合成气化学反应尺度耦合作用机理，阐明压力、富含氢气和合成气组分变化对合成气预混湍流燃烧和旋流稳燃燃烧火焰动力学的影响规律和作用机理，构建和改进合成气湍流燃烧模型。研究工作有利于提升我国在湍流燃烧领域的研究水平和国际影响力，为我国自主研发IGCC系统的合成气重型燃气轮机提供基础实验数据和理论支撑。

本项目系统开展了基于IGCC的合成气预混湍流燃烧特性基础研究，包括合成气层流火焰动力学研究、湍流火焰结构测量与表征、湍流与火焰相互作用基础研究。.1. 湍流与燃烧相互作用一方面是湍流涡对火焰反应区的扰动，另一方面，火焰自身对湍流和自身固有扰动的响应。火焰自身对固有扰动的响应，即层流火焰动力学理论对于理解湍流与燃烧相互作用非常重要。本项目利用OH-PLIF技术开展了层流火焰不稳定性和火焰动力学基础研究，包括预混层流火焰传播、平面火焰不稳定性和预混层流本生灯顶端熄灭结构。发展了层流火焰速度测量数据处理方法，对层流火焰加速传播过程的过渡阶段提出了新的认识。结合平面火焰胞状结构及其发展过程的定量测量、层流火焰本生灯顶端开口局部熄灭，丰富和发展了层流火焰不稳定性研究工作，为湍流与火焰相互作用研究提供了火焰动力学基础。.2. 湍流与火焰相互作用表现为复杂的褶皱火焰面凹凸结构，且呈现小尺度与大尺度叠加的多尺度结构，同时由于湍流火焰的随机脉动特性，其测量与表征非常复杂。湍流火焰结构，物理参数上表现为组分场、温度场、速度场等标量场分布信息，几何上体现为凹凸褶皱结构，是理解湍流与火焰相互作用机理，发展和验证湍流燃烧模型的基础。本项目利用连续燃烧预混湍流本生灯和OH-PLIF燃烧激光诊断技术，测量预混湍流火焰结构，发展了火焰结构图像提取和数据处理方法，发展了3D火焰面密度估计方法，为湍流燃烧实验研究奠定了基础。.3. 利用自主发展的可控预混湍流本生灯，采用OH-PLIF燃烧激光诊断技术，测量了合成气CO/H2/air、CH4/H2/air、C3H8/H2/air预混湍流火焰在不同初始压力、不同当量比、不同可控湍流场强度和尺度下的火焰结构，获得了湍流火焰速度实验数据，以及火焰面体积、火焰面密度、火焰曲率、火焰分形尺度等定量参数，发展了湍流火焰引导点理论，修正了湍流火焰分区图。研究结果发展了湍流火焰理论，为湍流燃烧模型构建和验证提供了理论和实验数据支撑。