Particle burning behaviors of Al/AP propellant with high-speed digital off-axis holography

The behavior of aluminum particles during Al/AP propellant combustion is studied by 25 kHz high-speed digital off-axis holography and high-speed microscopic imaging. The advantage of off-axis holography is that the effects of the enveloping flame are suppressed, thereby, achieving better burning particle imaging. Threedimensional dynamics of the aluminum particles from a series of time-resolved holograms are given in order to study the motion behaviors of particles during combustion. Typical processes, e.g., formation and change of the condensed phase products, micro-explosion behavior, and diameter ratio of enveloping flame and Al particle, are analyzed. This work provides a new 3D approach, that is, high-speed digital off-axis holographic imaging, for studying solid propellant combustion. (c) 2020 Published by Elsevier Inc. on behalf of The Combustion Institute.