Detailed characterization of fuel droplets in a spray flame using an integrated phase Doppler/Rainbow

摘要

The characteristics of fuel droplets burning in an unconfined, non-swirling spray flame have been experimentally studied in great detail using an integrated phase Doppler/Rainbow Refractometer system. This newly developed non-intrusive diagnosticinstrument allows for the measurement of individual fuel droplet temperatures in addition to their diameter and velocity. The fuel used for this study is hexadecane (C{sub}16H{sub}34) which has a boiling point of about 287°C. A solid cone Hago pressureatomizer with a flow rate of 0.5 gph was used to atomize the liquid fuel, and a spray flame was established by firing the atomizer vertically upward. Droplet temperature, size, and velocity data were obtained at several radial and axial locations withinthe spray flame. The study revealed that at the center of the spray, the droplets were well below their boiling point. Within the flame zone, the droplets had higher mean temperatures. A strong dependence of temperature on droplet size was also observedwithin the flame zone. The largest drops were close to room temperature whereas the temperature increased asymptotically to temperatures close to the boiling point with decreasing droplet diameters.