Laser monitor application for study of aluminum nanopowder ignition and combustion

Abstract

The paper presents the results of application of optical system with brightness amplification, a laser monitor, to study the surface of aluminum nanopowder at the time of laser ignition and during combustion. Using a laser monitor, we visualized the presence of a liquid phase in the process of laser ignition of aluminum nanopowder combustion for the first time. For quantitative analysis of the combustion process, we propose using the correlation coefficient of the images of laser monitor. The results of calculating the correlation coefficient demonstrated compliance with the change in the intensity of the images of the laser monitor during combustion and visual observation of the combustion process. For the conventional scheme of a laser monitor with a focal length of 8 cm, the distortions introduced by the instability of the brightness amplifier into the measurement results are estimated. When observing a static test object, the correlation coefficient of the images varied from 0.995 to 0.996, while the fluctuation in the correlation coefficient during combustion is in the range from 0.685 to 0.996, which indicates the possibility of this parameter usage for quantitative analysis of combustion processes in the study using a laser monitor.