Comparative analysis of bubble behavior between boiling and hydrogen evolving system at horizontal cylinders

We performed hydrogen evolving experiments using a water electrolysis varying diameters of horizontal cylinder. A series of still images of hydrogen bubble behavior near the critical current density were compared with bubble behavior of boiling system near the critical heat flux. At the critical current density, for a small cylinder case, the hydrogen film was formed by bubble agglomeration, while for a large cylinder case, the hydrogen film was formed by the collapsed column of the hydrogen mushroom. The same features are observed in the existing results with boiling systems. The hydrogen mushrooms were spaced by the critical Taylor instability wavelength and the size of hydrogen mushroom increased with the cylinder diameter, which is again similar to that of the boiling system. With further increase in cell potential, a stable film was formed with reduced size of the hydrogen mushroom. The critical current density decreased as the cylinder diameter increased. This work added some experimental evidence toward the analogy relationship between the boiling and hydrogen evolving system.