A Theoretical Model for the Formation of Functional Micro- and Nano-Particles from Combustion of Emulsion Droplets

In this paper a theoretical model is developed to simulate the process of vaporization and burning of emulsion droplets of a fuel and the evolution and formation of micro- and nano-particles. This process is usually known as the Emulsion Combustion Method (ECM). In the ECM, a proper salt solution is mixed with a fuel to form an emulsion of micro-solution droplets. The emulsion is then sprayed into micron-sized emulsion droplets; spray droplets burn in a spray flame to form final micro- or nano-particles. A mathematical model for the entire process from the droplet interior to the gas phase processes is proposed. Model equations are solved numerically. It is found that particle characteristics are dependent on the operating and processing conditions, such as the initial size and concentration of the suspended micro solution droplets in emulsion droplets and the fuel type and fraction of the emulsion droplets. Although a quantitative evaluation of the model performance is not yet possible due to the lack of sufficient experimental data, the developed model may be used to design an ECM process to produce particles with tailored properties. The main novelty of the model is that in an ECM process it can predict whether mono-dispersed single particles will be formed or agglomerated larger particles.