Validated numerical fluid simulation of a thin-layer cascade photobioreactor in OpenFOAM.

Abstract

Recently, microalgae have been considered as a promising alternative for the production of biofuels from CO2. For the efficient cultivation of these microalgae, several types of photobioreactors have been designed and Pilot scale photobioreactors have been used to assess the performance of these reactors. Therein the primarily investigated reactor type is the Raceway Pond. However, the less researched Thin-Layer Cascade Photobioreactor (TLC) shows a high potential for efficient production processes. Unfortunately, for low-value products like biofuels costs must be kept to a minimum for an economic operation. To facilitate this, 3D Computational Fluid Dynamic simulations can be employed to estimate performance of reactor variants e.g. with respect to power input and mixing. Since up to now little effort has been put into the modelling of TLC reactors, this report aims to present a simulation approach for these reactors types that allows simple adaptation to different geometric or operational boundary conditions. All models have been generated for a two-phase mixture in OpenFOAM. To demonstrate its applicability, validation measurements with a physical unit have been performed and were compared to the simulation results. With errors in the order of 10% a successful simulation of the reactor geometry could be proven.