Application of a digital high-speed camera system for combustion research by using UV laser diagnostics under microgravity at Bremen drop tower

摘要

Abstract: This paper describes a digital high-speed camera- andrecording system that will be used primary forcombustion research under microgravity ($mu@g) atBremen drop tower. To study the reactionzones duringthe process of combustion particularly OH-radicals aredetected 2D by using the method of laser inducedpredissociation fluorescence (LIPF). A pulsedhigh-energy excimer lasersystem combined with a two-staged intensified CCD-camera allows a repetition rateof 250 images (256 $MUL 256 pixel) per second,according to the maximum laser pulse repetition. Thelaser system is integrated at the top of the 110 m highevacutable drop tube. Motorized mirrors are necessaryto achieve a stable beam position within the area ofinterest during the drop of the experiment-capsule. Theduration of 1 drop will be 4.7 seconds (microgravityconditions). About 1500 images are captured and storedonboard the drop capsule 96 Mbyte RAM imagestoragesystem. After saving capsule and datas, aspecial PC-based image processing software visualizesthe movies and extracts physical information out of theimages. Now, after two and a half years of developmentsthe system is working operational and capable of hightemporal 2D LIPF- measuring of OH, H$-2$/O, O$-2$/, andCO concentrations and 2D temperature distribution ofthese species.!4