CFD Study of the Hydrogen Generation in an Electrolyzer with Applications in Thermal Machines

The emissions of greenhouse gases have significantly affected human health and put life on planet Earth at risk as known today. At present, different alternative fuels have been used in the partial or total replacement of fossil fuels in internal combustion engines, reducing greenhouse gas emissions. In this investigation, a CFD study is presented as the basis of a design methodology for electrolytic electrolyzers that operate with a solution of KOH-distilled water. Using OpenFOAM®, different operating conditions of an electrolyzer have been simulated in order to study the behavior of the hydrogen generation rate inside the device. A parametric analysis has been performed varying the voltage and the current, with different electrolyte concentrations, observing a 40% increase in current and a 3% reduction in voltage, comparing the concentration of 20% with the 40%. Above that concentration, no significant changes are achieved in the mass flow of generated hydrogen, but a 5% increase in consumption amperage for every 2% increase in concentration. Similarly, it has been observed that the velocity profile in which 5 m/s is reached within the electrolyzer in less than 6 s, which highlights the high dynamics of the process and the need to simulate it in order to optimize the design of such systems.