The Effect of Magnetic Field on the Dynamics of Gas Bubbles in Water Electrolysis
Abstract In this work, the movement of the gas bubbles evolved from the platinum electrodes in the influence of various magnetic field configurations are experimentally investigated. The oxygen and hydrogen bubbles respectively evolve from the surface of anode and cathode have distinctive behaviors in the presence of magnetic fields due to their paramagnetic and diamagnetic characteristics. The magnetic field perpendicular to the surface of the horizontal electrode induces the revolution of the bubbles. The opposite revolution direction between the oxygen and hydrogen bubbles cause the swirling of the flow and spread out the bubbles between the electrode which enhances the conductivity and electrolysis effectiveness. On the other hand, the vertical electrodes in the influence of a parallel magnetic field induce horizontal Lorentz force which effectively spells out the bubbles and increases the conductivity and electrolysis effectiveness as well. However, when the layouts of the electrode and magnetic field result in upward or downward Lorentz forces which competes with the buoyancy force, the sluggish flow in the duct would hinder the movement of the bubbles and decrease the conductivity and charging performance. This phenomenon affects the corresponding natural convection and mass transport as well. These results propose the optimal layout of the electrode and magnetic field which is useful to enhance the conductivity or the effectiveness in water electrolysis.