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基于多紫外相机的旋流火焰三维锋面层析重建

倪浩伟1,刘国炎1,周毅1,张彪2,柳伟杰3,许传龙4   

  1. 1. 东南大学大型发电装备安全运行与智能测控国家工程研究中心,能源与环境学院,南京 210096
    2. 东南大学能源与环境学院动力工程及自动化系
    3. 中国航空发动机研究院 基础与应用研究中心,北京 101304
    4. 东南大学能源与环境学院,能源信息与自动化系
  • 收稿日期:2022-11-29 修回日期:2023-01-13 出版日期:2023-02-01 发布日期:2023-02-01
  • 通讯作者: 许传龙
  • 基金资助:
    光谱光场成像发动机涡轮叶片表面温度场在线测量方法研究;基于偏振层析成像的碳烟颗粒浓度、粒径和形貌同步测量方法研究

3D Front Tomography Reconstruction of Swirl Flame by Ultraviolet Multi-Camera Imaging

  • Received:2022-11-29 Revised:2023-01-13 Online:2023-02-01 Published:2023-02-01

摘要: 旋流火焰锋面可表征火焰宏观结构和燃烧稳定性,其瞬态三维结构测量对旋流燃烧机理研究及旋流燃烧器优化设计具有重要意义。提出一种基于多紫外相机成像的测量方法,构建了基于多紫外相机阵列的化学发光层析成像系统(CTC),实现了低成本、高准确度的旋流火焰瞬态锋面化学发光信息获取;发展了基于预识别技术的联合代数重建算法(SART),通过光线追踪识别零强度体素,从而减少计算量和重建伪影。开展了数值模拟研究,以验证重建算法的准确性与抗噪性。最后搭建了甲烷-空气预混旋流燃烧实验台,开展了基于多紫外相机的化学发光成像系统标定和低旋流火焰锋面特性实验研究。结果表明,旋流火焰锋面反投影重建精度达到0.97以上,同时计算量减小了59.6%;稳定燃烧工况下,低旋流火焰在喷嘴出口处扩张,锋面呈现涡旋状的碗型结构;随着当量比的增大,火焰推举高度略有上升,火焰体积逐渐增大,燃烧稳定性增强。

关键词: 紫外成像, 旋流火焰, 锋面结构, 层析重建, 化学发光

Abstract: The front of swirl flame can be used to characterize the flame macrostructure and combustion stability, making the transi-ent 3D structure measurement extremely important for research on the swirl combustion mechanism and swirl burner optimization. In this work, a measuring approach for transient 3D front of swirl combustion flame by ultraviolet multi-camera imaging is proposed. In order to acquire transient chemiluminescence information at a cheap cost with high pre-cision, a computed tomography of chemiluminescence system (CTC) based on an ultraviolet multi-camera array is built. Additionally, the simultaneous algebraic reconstruction technique (SART) is improved using a pre-recognition method for non-intensity voxels identification by ray tracing, resulting in less computational load and reconstruction artifacts. Numer-ical simulation experiments are executed to confirm the precision and noise immunity of the reconstruction algorithm. A methane-air premixed swirl combustion experimental rig is built finally, then the calibration of the ultraviolet multi-camera imaging system and low-swirl flame front experiments are carried out. The results show that the inverse projection's ac-curacy exceeds 0.97 while the calculation is reduced by 59.6%. Secondly, the low swirl flame expands at the nozzle exit under stable combustion conditions and displays a vortex bowl-shaped structure. In addition, the flame pushing height rises slightly as the equivalent ratio grows, and the flame volume gradually increases as well, which enhances combus-tion stability.

Key words: Ultraviolet imaging, Swirl combustion flame, Front structure, 3-Dimensional tomographic reconstruction, Chemiluminescence

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