Emulsions are mixtures of immiscible liquids, such as oil and water, where one liquid is present in the form of polydisperse droplets. They play an essential role in various industrial applications, such as food processing, oil production or pharmaceutical processes. Recent research is exploring the application of fuel-water emulsions for more efficient and environmentally friendly power generation. An example is gasoline-water direct injection for future gasoline engines, which can be realized by emulsions. For this application, the stability of such emulsions is a key aspect. To better understand turbulent emulsions and their stability, they are investigated by means of Direct Numerical Simulations (DNS). Time resolved, three-dimensional DNS allows for a detailed study of the complex interaction between turbulence and the dynamics of the dispersed phase. Further, fluid properties and characteristic quantities can be specifically tuned in simulations, thus enabling a precise investigation of relevant setups. In our research, we study the effect of turbulence intensity and surface tension on the droplet size distribution and stability of turbulent emulsions. A special focus is on the segregation process and its characteristic timescale. By considering fluids of different densities, resulting in either oil-in-water or water-in-oil type emulsions, we are also able to analyze the segregation process driven by gravity.
