Construction of a test platform for hydrogen production from alkaline water and numerical simulation of the flow field distribution in the electrolytic cell

Electrolytic cells for alkaline water hydrogen production are a core component of the hydrogen production platform, and their performance affects the purity and efficiency of hydrogen production. To date, studies of electrolytic cells for alkaline water hydrogen production have mostly focused on the internal flow field distribution in the inlaid spherical convex and concave flow channels. Most electrolytic cells adopt a single-inlet design, preventing an analysis of the internal flow field distribution law within the flow channels when varying the number of inlets. For this purpose, an alkaline electrolytic water hydrogen production test platform with a hydrogen production capacity of 10 Nm³/h was fabricated. The effects of varying the system pressure and working temperature on the performance of the hydrogen production electrolytic cell were investigated. The results show that when the system pressure increases, both the electrolytic current and the oxygen content in the evolved hydrogen increase. When the working temperature rises, the electrolytic current increases and the oxygen content in hydrogen decreases. Based on the design parameters of the test platform, a single-inlet channel model of the electrode plate was constructed. In addition, electrode plate flow channels with double- and triple-inlets were designed. The flow field distribution characteristics within the flow channels were analyzed using computational fluid dynamics (CFD). The results show that the vortex distribution in the single-inlet and double-inlet flow channels is wide, forming a low-speed wake area, with a large velocity gradient and an uneven flow field. The vortex area of the triple-inlet flow channel is small, the flow field gradient is low, and the distribution is relatively uniform. This shows that the number and structure of the inlets significantly affect the turbulent kinetic energy of the electrolyte. A single-inlet channel is prone to form a highly turbulent zone, while double- and triple-inlet channels weaken the peak by diverting flow, making the turbulent kinetic energy distribution more uniform. Furthermore, the symmetrical structure of the double inlets can enhance the regularity of the turbulent kinetic energy distribution.