CFD modeling of multiphase flow in an alkaline water electrolyzer

The hydrodynamic properties of gas–liquid flows in water electrolyzers are of great practical interest since the local distribution of gas influences the amount of electrical energy required to produce hydrogen. We used the Euler-Euler model to simulate the multiphase flow in a water electrolyzer and compared the results to existing experimental data, for a range of current densities. Our study shows that if only the drag force and buoyancy force are incorporated in the model, the spreading of the gas layers formed at the electrodes is not accurately predicted. By adding the turbulence dispersion force to the model, reasonable agreement with the experimental data could be obtained for the higher current densities. The turbulence dispersion had to be implemented via user-defined functions, in order to obtain results that satisfied the momentum balance. In addition the effect of different turbulence models on the turbulent dispersion was investigated.