%A Haowei NI, Guoyan LIU, Yi ZHOU, Biao ZHANG, Weijie LIU, Chuanlong XU %T 3D front tomographic reconstruction of swirl flame by ultraviolet multi-camera imaging %0 Journal Article %D 2023 %J Acta Aeronautica et Astronautica Sinica %R 10.7527/S1000-6893.2022.28331 %P 128331-128331 %V 44 %N 18 %U {https://hkxb.buaa.edu.cn/CN/abstract/article_19436.shtml} %8 2023-09-25 %X

The front of swirl flame can be used to characterize the flame macrostructure and combustion stability, making its transient 3D structure measurement extremely important for research on the swirl combustion mechanism and swirl burner optimization. A measuring approach for the transient 3D front of swirl flame by ultraviolet multi-camera imaging is proposed. In order to acquire transient chemiluminescence information at a low cost with high precision, a Computed Tomography of Chemiluminescence (CTC) system based on 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. Numerical simulation experiments are executed to confirm the accuracy and noise immunity of the reconstruction algorithm. A methane-air premixed swirl combustion experimental rig is built finally, and the calibration of the ultraviolet multi-camera imaging system and low-swirl flame front experiments are carried out. The results show that the accuracy of the inverse projection exceeds 0.97 while the calculation is reduced by 59.6%. 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 combustion stability.