基于两波长激光吸收与散射技术的多组分燃料气液两相浓度场的同时测量

Laser diagnostics are indispensable means for research and design of fuel spray combustion in advanced gas turbine, rocket and automotive engines because optimizing combustion system needs to know details of liquid atomization, droplet evaporation, fuel-air mixing. However, an imaging system which enable simultaneous and quantitative measurement of the liquid and vapor phase distributions of each component in a multicomponent fuel spray is still not available yet. This project will propose a laser diagnostic, based on ultraviolet/visible 2-wavelength laser absorption-scattering (LAS) imaging, to simultaneously and quantitatively measure both vapor and liquid phases in a multicomponent fuel spray. The key issues to be covered are 1) how to separate signals from liquid and vapor phases; 2) how to decrease measurement error resulting from the different extinction efficiencies at the two wavelengths; 3) how to distinguish the signal of each components in the multicomponent fuel without penalty for the component substitute. When these scientific problems are clarified, the laser diagnostics device will be built, which consists of lasers, incidence optical system, receiving devices, data acquisition and imaging-processing software, based on the principle proposed. It is expected that this equipment will be a powerful and accurate instrument for studies on fuel spray, evaporation and fuel-air mixing processes, and significantly improve the instrumentations for exploring the relation between fuel mixing and ignition, combustion and emissions, and for effectively controlling the combustion processes and optimizing the combustion system.

发动机燃烧技术在空天技术和汽车技术领域中至关重要，而先进的燃烧测试技术则为液体燃料燃烧研究提供重要手段。本项目拟根据紫外光和可见光透过燃料蒸气吸收和液滴散射而消光的原理，开发一种可以同时定量测量多组分燃料喷雾中液滴和蒸气两相浓度分布的激光诊断系统。着重解决来自气液两相信号分离、液滴对不同波长的消光度差异所带来的定量标定困难、多组分同时测量时模拟燃料的组分及配比确定等关键问题。在此基础上构筑由激光光源、入射光学系、接受光学系、数据采集及图像分析后处理等四部分组成的测试系统。通过本研究解决多组分燃油喷雾以及两相流中的气液两相浓度分布的同时定量测量这一国际上长期没有解决的难题，为探明液体燃料火箭、航空和汽车发动机中液体燃料喷雾的雾化、蒸发、混合过程的特征与规律，揭示浓度场与着火、燃烧、排放的内在关系，为发展液体燃料燃烧科学与技术提供有效的测试手段和工具。

发动机燃烧技术在航空航天技术和汽车技术领域中至关重要，而先进的燃烧测试技术则为液体燃料燃烧研究提供重要手段。本项目依据紫外光和可见光的吸收与散射原理，开发了一种同时测量多组分燃料喷雾气液两相浓度分布的二维激光诊断技术，并构筑了紫外/可见激光吸收与散射测量（Ultraviolet-visible laser absorption-scattering technique ,UV-LAS）实验系统，完成了适用于汽油、柴油等实际燃料的多组分替代燃料的气液相浓度分布的测量。将该技术应用于直喷汽油喷雾的闪沸喷雾、车用柴油碰壁喷雾、船用柴油喷雾等课题的研究并且取得显著成果，同时在原有两个波长测量的基础上扩展为三个波长的测量，完成了喷雾气液浓度以及温度场分布的同时测量。通过本项目的研究，解决了多组分燃油喷雾以及两相流中的气液两相浓度/质量分布的同时测量这一国际难题，为研究汽车发动机、液体燃料火箭发动机、航空燃烧系统中的燃油雾化-蒸发-混合过程以及研究混合气浓度分布与稳定着火、高效燃烧、碳烟生成控制的关系等提供有效的测试手段。