NUMERICAL STUDY ON HYDROGEN BUBBLE PRODUCTION AND OVERPOTENTIAL IN WATER ELECTROLYSIS

In water electrolysis, bubbles generated between electrodes increase the electric potential required for water splitting. In this work, a numerical analysis of bubbly flow in water electrolysis is conducted using an Eulerian two-fluid method to investigate the interaction of bubble generation and electric potential. The electric potential field is solved by combining with a Tafel equation to consider the overpotential in an electrolysis cell. The present simulation demonstrates that the ohm resistance within the fluid region increases nonlinearly as the electric current density increases, indicating that the hydrogen production efficiency decreases at high current densities. The inlet velocity is observed to be a key factor to decrease the ohm resistance within the fluid region. The effects of inlet velocity and current density on the bubbly flow and electric overpotential are investigated.