Master theses / Diploma theses / Student Assistant

The growth of hydrogen bubbles in water electrolysis is a particularly interesting problem of high practical relevance due to the prominent role of hydrogen in energy storage via power-to-gas processes. The dynamics even of a single bubble are already multifaceted and associated with a number of interdisciplinary phenomena such as Marangoni convection, bubble-microlayer interaction, or electric effect resulting from the interplay of electric field and surface charge of a bubble.

PROBLEM: Our recent work shows a noticeable role of the electric force in the bubble dynamics, e.g. in bubble oscillations. The electric effect, in that case, was established as a restoring force triggering a return mechanism of the bubble once detached from the electrode surface. In such a way, the depended on the bubble position electric force causes long-lasting position oscillations. As an extension to ongoing work a new phenomenon related to electric effect was preliminary observed. The essence of that is the ability of the bubble moves oppositely to the gravity force direction under the electric force influence and returns back to the electrode from relatively large distances (appx. 300 μm).

OBJECTIVE:

• A systematic experimental study of the phenomenon by the shadowgraphy and electric current measurement techniques
• Data analysis via Matlab

• Study in fluid dynamics, process engineering, chemical engineering (or comparative field of study)
• Motivation and eagerness
• Good written and oral communication skills in English
• Optimally: experimental experience, Matlab basics

Duration ca. 6 months, start: from October. 2020, workplace: HZDR. Possible to combine a student assistant work or internship with Master/ Diploma theses.