基于新型双向PLIF的高精度稳态燃烧场活泼自由基浓度定量测量技术研究

Bi-directional planar laser-induced fluorescence (BD-PLIF) has been regarded as a calibration-free quantitative laser spectroscopy technique which is not affected by quenching effect. It can be used to achieve the quantitative measurements of species concentration with high spatial resolution in stable combustion field. Therefore, it has great significance for the research of basic science and applied technology. This project aims for studying the high precision bi-directional PLIF species concentration measurement technology. For the important difficulties in improving the quantitative measurement capability and accuracy of the system, a novel bi-directional PLIF quantitative measurement technique will be first constructed and realized for the first time, by innovative combining a fully reflective quartz square rod coupling mechanism uniformization system and a long focal depth sheet forming optics. On this basis, a complete and correct physical model of the interaction between the effective peak absorption cross section and the physical parameters will be studied in depth and established, so as to optimize the measurement accuracy of the effective peak absorption cross section. The result will be used to improve the measurement accuracy of the new bi-directional PLIF. At last, the accuracy and the error sources for the concentration measurement results will be analyzed, so as to develop a complete bi-directional PLIF error assessment model and explore an effective error compensation method. In summary, the project will invent a new type bi-directional PLIF technology firstly. And the accuracy of quantitative concentration measurement could be enhanced by research on several key scientific issues. The final purpose of the project is to provide new technical method and scientific guidance for high-precision quantitative measurement of species concentration in stable combustion field.

双向平面激光诱导荧光技术是一种不受淬灭效应影响的免定标定量激光光谱测量技术，可实现高空间分辨率稳态燃烧场组分浓度定量测量，对于基础科学和应用技术研究都具有非常重要的意义。本项目将对高精度双向PLIF组分浓度测量技术展开研究。针对提高双向PLIF系统定量测量能力和测量精度的关键难题，首先创新性地采用基于全反射式石英方棒耦合机制的长焦深片光均匀化系统首次构建新型双向PLIF定量测量技术。在此基础上，深入研究并建立完整正确的有效峰值吸收截面与各物理参量相互影响的物理模型，优化有效峰值吸收截面测量精度，进而提升新型双向PLIF的测量精度。最后，分析新型双向PLIF技术组分浓度测量结果准确性和误差来源，建立完整的误差评估模型并探索有效的误差补偿方法。即本研究将首先构建一种新型双向PLIF技术，并通过关键科学问题的研究提高其测量精度，最终为稳态燃烧场组分浓度的高精度定量测量提供新型技术手段和科学指导。

双向PLIF技术是一种无淬灭影响的免定标定量激光诊断技术，对于燃烧科学及其应用技术具有非常重要的意义。本项目针对提高双向PLIF系统定量测量精度的关键难题，创新性地提出了基于全反射均光腔的长焦深片光能量均匀化整形技术，并以此构建了基于该技术的新型双向PLIF测量系统。然后，建立了较为完整的有效峰值吸收截面与各物理参量相互影响的物理模型，并探索了这些影响因素对有效峰值吸收截面的影响规律。最后，建立了完整的误差评估模型，分析了新型双向PLIF技术组分浓度测量结果准确性和误差来源，探索了有效的误差补偿方法。通过本项目的研究：（1）构建了基于全反射均光腔的长焦深片光能量均匀化整形光学技术的新型双向PLIF测量系统，将片光均匀性提升至97%、焦深提升至60 mm，有助于提升双向PLIF系统的测量精度；（2）基于新型双向PLIF测量系统，实现了标准平焰OH基浓度场的二维高空间分辨绝对定量测量，空间分辨率可达90 μm，测量区域（长×高）可达40 mm × 30 mm；（3）探索了OH基有效峰值吸收截面与各物理参量（激发波长、激光能量密度、温度、主要碰撞环境N2、CO2、H2O）的相互影响的物理模型。实验研究发现：N2碰撞环境下的OH基有效峰值吸收截面最大，其次为CO2，最小的是H2O，与理论预测相符；（4）实验验证了双向PLIF测量准确性，研究表明双向PLIF与传统单向定标PLIF、紫外吸收光谱技术、GRI-3.0燃烧机理仿真在轴向的变化趋势完全相同，且与其他方法测量的数量级也相同，均为10e16 cm-3。同时，建立了较为完整的双向PLIF误差评估模型，给出了主要误差来源的误差补偿方法。总之，通过本项目的研究，实现了测量稳态燃烧场活泼自由基浓度场的新方法，并建立了有效峰值吸收截面与各物理参量相互影响的物理模型，验证了双向PLIF测量的准确性，建立了较为完整的误差评估模型，用于发现本质规律。同时，基于这些研究结果，还在本领域国际知名期刊上发表了三篇较高水平的学术论文，扩大了国内研究学者在国际学术领域的影响。