Spray Characterization
Sprays used in advanced energy conversion systems are typically characterized by complex physical and chemical processes such as turbulence, droplet formation, droplet collision, droplet evaporation, combustion, and soot generation. Detailed and complete characterization of spray characteristics in realistic environments is extremely challenging but necessary for the development of high fuel efficiency and low emission systems. Besides energy related applications, there are several other industrial, medical, and agricultural applications that involve sprays and droplet streams that require the study of droplet dynamics. These include quality control, coating, cooling, painting, scrubbing, crop pesticide spraying, inkjet printing, medical inhalers, and nebulizers. Typically, a variety of measurement techniques are employed to measure parameters such as spray angle, sheet thickness, droplet size, droplet velocity, and droplet temperatures among others. The simultaneous measurement of individual droplet size and its velocity in a polydisperse environment is particularly important to the understanding of the spray formation and its dynamics.
Artium offers a variety of off-the-shelf and customized instruments that operate on the principles of Phase Doppler Interferometry (PDI) for simultaneously measuring the size and velocity of individual spherical droplets and particles in reactive and non-reactive sprays. In PDI, which is an extension of the Laser Doppler Velocimeter (LDV), the light scattered by spherical droplets is analyzed to make the measurements in a completely non-intrusive manner. The information derived from individual droplets is subsequently used to compute various spray statistics including size histogram, size-velocity correlation, Sauter mean diameter, number density and liquid volume flux. The PDI technique was invented and developed by Artium scientists and is recognized world-wide as the most reliable and accurate means for spray characterization.