A Near–Far-Field Model for Bubbles Influenced by External Electrical Fields

• Main Authors: Juergen Geiser, Paul Mertin
• Format: Article
• Language: English
• Published: MDPI AG 2019-11-01
• Series: Applied Sciences
• Subjects: bubble formation; dielectric fluids; electrical field; scale-dependent models; near–far-field approach; young–laplace equation; convection-diffusion equation; level-set method; coupling analysis
• Online Access: https://www.mdpi.com/2076-3417/9/21/4722

In this paper, we present a model that is based on near−far-field charged bubble formation and transportation in an underlying dielectric liquid. The bubbles are controlled by the dielectric liquid, which is influenced by an external electrical field. This allows us to control the shape and volume of the bubbles in the dielectric liquid, such as water. These simulations are important to close the gap between the formation of charged bubbles, which is a fine-scale model and their transport in the underlying liquid, which is a coarse-scale model. In the fine-scale model, the formation of the bubbles and their influence of the electric-stress is approached by a near-field model, which is done by the Young−Laplace equation plus additional force-terms. In the coarse-scale model, the transport of the bubbles is approached by a far-field model, which is done with a convection-diffusion equation. The models are coupled with a bubble in cell scheme, which interpolates between the fine and coarse scales of the different models. Such a scale-dependent approach allows us to apply optimal numerical solvers for the different fine and coarse time and space scales and help to foresee the fluctuations of the charged bubbles in the E-field. We discuss the modeling approaches, numerical solver methods and we present the numerical results for the near−far-field bubble formation and transport model in a dielectric carrier fluid.