抄録
The group combustion behaviour in a premixed spray was observed in detail by simultaneous optical diagnostics. Mie scattering images of droplets illuminated by a laser light sheet were obtained in time series by a high-speed camera. In addition, at a particular point in the target region of the images, time-series signals of the light emission in OH and CH bands, and the Mie scattering from droplets was detected by a specially designed receiving optics, Multi-color Integrated Receiving Optics (MICRO), and the size and velocity of droplets with a phase Doppler anemometer (PDA) were monitored, simultaneously. The high data rate and high validation rate of PDA measurement accomplished by the optimized design of PDA optics enabled us to distinguish instantaneous characteristics of individual droplet clusters in the flame. Thus, we estimated the group combustion number G_C for individual droplet clusters using the measured mean separation distance between droplet centers and the total number of droplets in each droplet cluster.
