Innovative extension for the simulation of electret filter media

Electret filters are widely used in many industries due to their high filtration efficiency. These filters operate on the principle of electrostatic attraction between charged fibers and particles. Nevertheless, research on electret filter media involves addressing various challenges and complexities, including the charge stability over time, charge uniformity, the optimization of the performance across a broad range of particle sizes, etc.

Numerical simulations contribute to a deeper understanding of the fundamental mechanisms governing the behavior of electret filter media. Simulations provide useful insights into the complex interplay of electrostatic forces, airflow dynamics, and particle behavior, not be easily observed or measured experimentally. GeoDict stands out as a powerful software tool designed for simulating particulate filtration within filter media and elements. As part of the publicly funded ElekSim project, the FilterDict module is  improved. This addition specifically focuses on simulating electrostatic effects. It brings in several new capabilities, such as simulating different charge distributions in both particles and fibers, modeling electrophoresis, and tracking the surface charge decay in electret filter media.

The methodology to simulate the electrostatic effects is first validated by comparing it to the results obtained from Fluent® using a single fiber model. The filter efficiency for different particle sizes is computed. Subsequently, realistic random fibrous filter medium structures are simulated to study the effects of the influences of different surface charge distributions on fibers, the charge density, the dielectric forces, as well as charge decay.

The objective of the work is to develop a new simulation environment tailored for electret filters, aiming to streamline the optimization of electret filter media design by quickly evaluating various material properties, charge distribution methods, and structural configurations.