Optical System with Brightness Amplification for Monitoring the Combustion of Aluminum-Based Nanopowders

This paper presents the results of real-time monitoring of air combustion of aluminum nanopowder and its mixtures with aluminum micropowder and iron oxide III. An optical system with a brightness amplifier was used along with visual monitoring to characterize the reflectivity of the sample surface. The reflectivity was analyzed after registering by a photodiode the intensity of radiation reflected from the surface and then amplified by the brightness amplifier at 510.6-and 578.2-nm wavelengths. Analysis of the images obtained with a high-speed camera and the photodiode output oscillograms showed that the intensity of the brightness amplifier output corresponds to the main stages of the combustion process, including the beginning of combustion, spreading of the heat wave and rise of the second combustion wave. The proposed technique is adequate for real-time monitoring of the combustion process with temperatures of 2200 °C-2400 °C, which is accompanied by intensive lighting.