Toward formulating coalescence filtration: Characterizing wetting saturation via centrifugal force

• Published in: International journal of multiphase flow 2024-01, Vol.170, p.104641, Article 104641
• Main Authors: Bhatta, Nishant, Tafreshi, Hooman V., Pourdeyhimi, Behnam
• Format: Article
• Language: English
• Subjects: Bubble point pressure; Capillary pressure; Centrifugal desaturation; Coalescence filtration; Multiphase; VOF; Wetting saturation
• ISSN: 0301-9322; 1879-3533
• DOI: 10.1016/j.ijmultiphaseflow.2023.104641

Coalescence filtration is the removal of dispersed droplets from a gas or from an immiscible liquid using a fibrous filter. Coalescing filters operate under a partially-saturated condition where some of the filter pores are filled with accumulated droplets. To date, there exists no theory that can predict the filtration efficiency of a coalescing filter and this is due to the complicated coupling between the aerodynamic field inside the filter and the capillarity of the fibers. This paper presents a new approach to study coalescence filtration by replacing the aerodynamic field inside the filter with a centrifugal force field and to thereby decouple the role of fiber properties from that of the airflow in fluid accumulation in a filter. This paper is only the first step towards developing the above mathematical theory for coalescence filtration. In the current study, we use numerical simulation and experiment to compare desaturation of a liquid-saturated fibrous media via centrifugal force (new) and via compressed air (traditional). For the simulations, we used the volume-of-fluid (VOF) method implemented in ANSYS software, and for the experiments, we used a Porometer for the pressure-driven desaturation, and a custom-made setup inside a swing-bucket centrifuge for the centrifugal desaturation. The experiments were conducted using a nonwoven fabric infused with mineral oil. Pressure-driven and centrifugal desaturation processes were compared with one another, and the advantages of the latter were discussed in detail. [Display omitted] •A roadmap is proposed towards the development of a theory for coalescence filtration.•Centrifugal force is proposed as a method characterizing wetting saturation in filters.•The centrifugal method allows for decoupling of airflow from wetting saturation.•Comparison is given for desaturation via centrifugal and via pressure-driven methods.