Numerical and experimental investigation of irradiance profiles on suspended particles in a flat disk photoreactor for hydrogen generation

[Display omitted] •A flat disk reactor for photocatalytic hydrogen production from H2O is proposed.•Computational fluid dynamics simulation and experimental validation is developed.•Irradiation exposure profiles of particles within the stirring fluid were determined.•Maximum model agreement of 84.7% for particle concentration is achieved. Regarding sustainable energy alternatives, the present work evaluates hydrogen production using suspended particles exposed to an irradiance of 247 W/m2. A 1.0 L flat disk photoreactor (FDP) was designed for evaluating agitation speeds of 100, 175, and 250 RPM, and particle concentrations of 0.5, 1.0, and 2.0 g/L. Through CFD-assisted, a non-conformal meshing of 551,000 polyhedral elements was created, coupling Volume of Fluids, Discrete Particle Modelling, and Discrete Ordinates Model methods. Transient simulation shows a maximum particle homogenization of 84 % at 0.5 g/L and 250 RPM, and a maximum average exposure profile of 140 W/m2 for 27% of the particles with an initial loading of 1.0 g/L at 250 RPM. Effective concentration in the FDP was measured, determining an accuracy of 84.35% and 71.32%, respectively, concerning the model used in the simulation. It is concluded that the FDP developed provides good semiconductor behavior for an effective hydrogen production process.