Measuring three-dimensional bubble dynamics for hydrogen production via water electrolysis.

This article focuses on the development and application of a stereoscopic shadowgraph imaging system combined with advanced image processing and particle tracking velocimetry (PTV) algorithms to quantitatively measure the three-dimensional (3D) characteristics of micrometer-scale hydrogen bubbles generated during alkaline water electrolysis (AWE). The study introduces a bubble-size adaptive detection algorithm and a bubble-size-assisted two-view 3D PTV algorithm to accurately identify bubble size, position, and velocity, validated through synthetic data. Experimental results reveal that bubble trajectories exhibit lateral motion influenced by bubble flow rate, with the coarse Ni mesh electrode producing smaller bubbles at higher detachment frequencies compared to a smooth Ni plate electrode. The rise velocity of bubbles correlates positively with bubble size but deviates from theoretical predictions for larger bubbles due to non-buoyancy effects such as electrolyte-induced drag. The proposed measurement technique offers effective volumetric diagnostics essential for optimizing electrode design and bubble management in electrochemical hydrogen production systems.