Single oxygen bubble dynamics

Part of Project OXYSEP

Contact persons: Prof. Dr. et Ing. habil. Kerstin Eckert, Dr. Xuegeng Yang, Dr.-Ing. Karin Schwarzenberger

Person involved: M. Sc. Hongfei Dai

For the new generation of PEM electrolysers, the central components in phase separator or in heat exchanger are based on additively manufactured components from LINDE AG with defined surface roughness. For the additively manufactured components (the M x N matrix), model experiments are carried out with artificially introduced O₂ single bubble. The growth of these bubbles (radius and contact angle as a function of time) is measured at different supersaturations. In parallel, the spatial oxygen concentration as a driver of growth is measured by interferometer, LIF, PIV etc. Optical Measurement Technology is mainly used in these measurements, because the Optical Measurement Technology has the advantages of non-invasiveness, accuracy etc. The measurement results are used as a reasonable design guide for further material development. At the same time, the feature of oxygen bubble growth dynamics under different surface functionalization and the theoretical models provide a theoretical basis for practical applications. And this work contributes to the improvement of the overall efficiency of SINEWAVE PEM electrolysers.

Goals

• Analysis of growing mechanism of the oxygen bubble in ultrapure water;
• characterize dissolved oxygen concentration field around a growing(shrinking) oxygen bubble;
• Description of coalescence of two oxygen bubbles;

Technology                               

• Shadowgraph                                       
• Laser-induced fluorescence (LIF) 
• Interferometry
• Particle Image Velocimetry
• Laser diffraction
• dynamic light scatter

© Hongfei Dai

Analysis

• Bubble dynamics analysis
• Diffusion dynamics analysis
• Concentration field analysis
• Coalescence of two oxygen bubbles analysis
• Zeta potential analysis