It is now possible to calculate coalescence using GeoDict! Users can simulate the coalescence of small droplets on the scale of the filter medium. With this new feature, users can model and simulate a variety of new applications of filtration processes such as oil/water separators, droplet separators, and condensers.

In numerous industrial applications, liquid aerosol particles are generated, which can be toxic or harmful to humans and can also affect the efficiency of industrial products and equipment. Additionally, natural liquid droplets such as viruses produced during exhalation can transmit diseases like Covid-19.

The process of droplet separation (coalescence) is a crucial process for separating two phases (liquid/liquid or liquid/gas) and is much more complex and less studied than the classical separation of solid aerosols. Coalescence also plays a significant role in improving filtration efficiency, especially in HVAC (Heating, Ventilation, and Air Conditioning) systems. HVAC systems are responsible for maintaining a comfortable and healthy indoor environment by regulating temperature, humidity, and air quality.

Coalescence occurs when small droplets in a liquid unite to form larger entities. These agglomerates grow until they either drain at the bottom of the medium due to their size (drainage) or are entrained by the surrounding flow and fall to the ground (re-entrainment). If the inflow velocity is too high, the entrained droplets are often very small and can be reintroduced into the airflow.

To counteract this behavior, it is now possible to model, simulate, and visualize coalescence phenomena using GeoDict. This enables predicting the temporal increase in pressure drop with different contact angles between droplets and the filter medium and optimizing the filter medium itself for continuously increasing requirements in various application areas.

Furthermore, several studies have shown that fibers with different patterns of, for example, oleophilic and oleophobic surfaces can improve drainage properties and significantly reduce the maximum differential pressure at saturation. GeoDict also supports fiber generation with the aforementioned properties.

In summary, GeoDict provides access to a more comprehensive understanding of coalescence phenomena and paves the way for even better filtration processes.

 

In this video, the deposition of particles in a filter media is simulated, taking coalescence into account.