In-situ observation of oil structures and their influence on filtration efficiency in the coalescence region of oil mist filters with oleophilic media

Submicron airborne oil droplets (oil mist) are generated as an unwanted by-product in various processes, for example in compressed air generation with oil-lubricated screw compressors. For reasons of health and environmental protection as well as occupational safety, they are usually removed using coalescence filters consisting of several layers of a fibrous material (often micro glass fibers). With increasing oil saturation, small droplets in the filter medium grow into larger oil structures and oil channels, and, depending on the wettability, an oil film forms on the upstream or downstream side. The resulting functional regions (coalescence, channel and film region) contribute differently to the total penetration. How deposited oil structures in the first fiber layers of the first filter layer (i.e. the coalescence region) influence filtration at the onset of saturation is not yet fully understood.

Since industrially manufactured filter layers are unsuitable due to their thickness, very thin, in-house manufactured filter media are used to investigate the coalescence region. The optical system integrated into the test rig allows the thin filter layers to be observed at the micrometer scale during loading, making oil structures and fibers visible. The aim is to characterize the contribution of the coalescence region to the total penetration at different saturations and filtration velocities as well as for different fiber diameters.

Scope of the thesis:

In this work, experimental investigations will be carried out on very thin filter layers in the test rig. The filtration efficiency and the pressure drop will be determined with increasing oil loading. The optically observed oil structures will be related to the filtration efficiency by means of image analysis. The filtration velocity and the fiber diameter will be varied. The scope of the work can be adapted to your interests and available time depending on whether it is a Master’s or Bachelor’s thesis is. The thesis can be written in English or German.

What you should bring:

• Interest in the topic and enjoyment of experimental work
• A high degree of independence
• Goal-oriented working style and flexibility
• Communication skills
• Basic knowledge or interest in Python is an advantage, but not a must

What I can offer:

• Regular meetings and supervision
• Flexible support with problems and questions
• Insight into a DFG-funded research project

If you are interested in this project, feel free to send me an email telling me a bit about yourself, what you expect from the work and when you would like to start. I will then send you an appointment where we can discuss everything in person and you can see the test rig. I would be happy to hear from you.

Contact:

M.Sc. Özge Yavuz
Email: oezge.yavuz∂kit.edu
Phone: +49 721 608-42515

Straße am Forum 8
Building 30.70, Room 111
76131 Karlsruhe