Atomizer kerosene spray flame

Figure 5. Flame photograph— tioin-fluid atomizer kerosene spray fame...

Measurements have been made of the combustion characteristics of an air blast kerosene spray flame and of droplet sizes within the spray boundary of isothermal sprays. Specific techniques were used to measure velocity, temperature, concentration, and droplet size. Velocities measured by laser anemometer in spray flames in some areas are 400% higher than those in isothermal sprays. Temperature profiles are similar to those of gaseous diffusion flames. Gas analyses indicate the formation of intermediate reactants, e.g., CO and Hg, in the cracking process. Rosin-Rammler mean size and size distribution of droplets in isothermal sprays are related to atomizer efficiency and subsequent secondary atomizer/vaporization effects. 

Air from the compressor enters the mixing chamber of the atomizer at sonic velocity and, after interaction with the liquid kerosene stream, emerges as a two-phase mixture, directed vertically upwards. The air flow from the annular stream forms a recirculation zone in the wake of the stabilizer disk. The flame is ignited by an external gas stream and subsequently bums independently as a flame in the open atmosphere. Droplets are initially confined to the air jet from the atomizer nozzle, but some of the finer droplets are taken up by the reverse flow of the stabilizer disk recirculation zone. Previous studies on spray combustion and details of atomizer design are reviewed by Chigier (J). 

Takatori and his collaborators in Toyota Research Center were one of the first who developed and systematically studied the emulsion combustion method (ECM) [3]. This method is basically a combination of the microemulsion wet chemistry and the flame spray pyrolysis methods. In ECM, an aqueous solution of a metal salt is mixed with a fuel such as kerosene and a small amount of an emulsifier or surfactant to obtain a water-in-oil (W/O) type of emulsion. Using a spray nozzle, the solution is then atomized to produce a spray. The size of the mother emulsion droplets depends on the atomizer type and the atomization conditimis, and is on the order of 10 pm for air-assist nozzles. The size of the dispersed micro-solution droplets depends on the string process and surfactant, and is about 1 pm [3]. Figure 40.1 shows a schematic diagram of the ECM. 

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