Abstract
To elucidate detailed combustion mechanism of droplet clusters, that is, group combustion behavior, simultaneous time-series measurements of OH chemiluminescence, CH-band light emission, and Mie scattering from droplets illuminated by laser light detected by using a Cassegrain optics named MICRO (Multi-Color Integrated Cassegrain Optics), the droplet diameter and velocity measured by using PDA are applied to a premixed spray flame. In addition, time-series planar images of droplet clusters are obtained simultaneously with these 5 quantities mentioned above to observe the combustion process of droplet clusters. The high data rate and high validation rate of PDA measurement accomplished by the optimized design of optics enabled us to distinguish instantaneous characteristics of individual droplet clusters in the flame. Thus, we estimated the modified group combustion number GC for individual droplet clusters using the cross-section area, the measured mean separation distance between droplet centers, the total number of droplets for each droplet cluster.
