CFD modelling of convective falling films for enhanced algae cultivation : fluid mechanics influence of mass transfer

Abstract

Falling film photobioreactors are able to increase the mass transfer rates per volume of liquid through the gas-liquid interface compared to other photobioreactor types. At low Reynolds numbers the flow mass transfer is still diffusion limited. This work aims to resolve and improve the convective mixing within thin falling films numerically to optimize the rates of CO2 absorption into a thin falling water film. Flat plate models are compared and it is found that slower films with a Reynolds number of 28 outperform faster flowing films by up to 2.5 times.