EVALUATION OF ATOMIZATION TIMING AND OPTIMAL WATER CONTENT FOR AN EMULSIFIED FUEL DROPLET 2018-32-0059
The emulsified fuel means that mixed the fuel with water and stabilized by surfactant. The difference of boiling point between fuel and water occur the secondary atmization in the heating process. The water content strongly influence on the timing of secondary atomization. However, the water content is determined empirically. It means it is the doubtful of compatibility fuel and combustor. Then the emulsified fuel is needed the engineering evaluation (not empirically) for taking advantage of sure secondary atomization.
This research focuses on the timing and behaviour of secondary atomization of an emulsified fuel droplet and the proposal of engineering evaluation. Moreover, we propose novel test method without the suspending wire to avoid heat transfer from itself. Namely, the novel point is heating process by floating in the high temperature silicone oil. This method can reveal the atomization behaviour of fuel droplets similar to the spray combustion.
The measured data are waiting time of atomization and direct photos at heating process. The waiting time is fitted by Weibull plots which is a statistical treatment. The inclination of Weibull plots means the timing of secondary atomization. This is the engineering evaluation on this research.
The experimental results show the optimum water content of Hexadecane is 23% by this evaluation method. If the fuel droplets have different timing of the secondary atomization, it is hard to control the combustion, for example, ignition delay, rate of heat release and so on. The typical experimental results show the inclination of Weible Plots converge to a point. This is mean that even various sizes of fuel droplets occur secondary atomization in the same timing in the heating process. The optimum water content of Bio diesel fuel is wide range under 30%. We propose the statistical evaluation to determine the optimum water content for practical emulsified fuel.
Junichi Aoki, Junya Tanaka
Graduate school of Kogakuin University
SAE/JSAE Small Engine Technology Conference