Study of the Spatial Distribution of Burning Particles in a Pyrotechnic Flame Based on Particle Velocity.

The burning particles in the pyrotechnic flame play an important role in the ignition and spectral radiance of the pyrotechnic. We used particle image velocimetry (PIV) and high-speed camera (HSC) photography to investigate the 3D spatial pattern and velocity of the burning particles in the flame of pyrotechnics. The original images captured by the HSC were preprocessed through threshold selection, image bivalency, edge detection, and contour extraction and segmentation to obtain the particle coordinates and velocity. Consequently, the particle tracking model was established and the velocity and spatial distribution of the burning particles were obtained. A comparison of the flame flow field with particle image velocimetry demonstrated the typical characteristics of the two-phase flow of the pyrotechnic flame between burning particles and gas. Compared with the convergent gas flow field, the higher velocity burning particles had a discrete distribution in the “comet tail” shape region and showed the same direction of motion as the flame flow field, whereas the lower velocity burning particles had larger outlying regions and showed inconsistent directions of motion. The flow field of the burning particles was more chaotic than the flame flow field of the burning pyrotechnics. [ABSTRACT FROM AUTHOR]