Studies on the Flame Structure of a Spray Burner : 2nd Report, Experimental Comparison with the Gas Diffusion Flame and Discussion on the Behavior of Droplets

Abstract

It was conjectured in the first report that most of the droplets within the flame do not burn individually, but fuel vapor evaporated from them collects and burns like a gas diffusion flame. The main object of this study is to confirm this conjecture. First, various measurements were made on a spray combustion flame and a gas diffusion flame under the same conditions. Comparing the two sets of data, it was found that the flames are similar in structure. Experiments on five spray combustion flames having different sizes, produced by changing the flow rate of combustion air, were secondly conducted. From the results, the conjecture of the first report was confirmed and it was found that the turbulent diffusion process has much greater influence upon the shape of the flames used in this study than the evaporation process of droplets. Finally, assuming that the droplets simply evaporate within the flame, their behavior was analyzed by making use of the knowledge which has been obtained for a single droplet. The calculated results showed fairly close agreement with the measured results.