Investigation of Water Turbulence Effects on Microalgal Cell Wall Damage in Thin-Layer Cascade Systems: A Fluid–Structure Interaction Approach

Turbulent flow mixing plays a critical role in optimising microalgal cultivation in thin-layer cascade (TLC) systems. However, the small size of microalgal cells makes them highly susceptible to hydrodynamic stresses generated by turbulent mixing. The mechanical properties of microalgal cell walls under turbulent conditions and their implications on cell viability and biofuel production in TLC systems remain largely unexplored. In this study, a novel fluid–structure interaction-based numerical model was developed to investigate the effects of turbulent mixing on microalgal cell wall damage in TLC systems. This study focused on assessing cell wall damage at various locations within the TLC system, considering the hydrodynamic and geometric characteristics of the system. It examined parameters such as aspect ratio, flow depth and mass flow rate to analyse cell wall shear stress, deformation and von Misses stress. Results demonstrated that appropriate turbulent mixing conditions are crucial in TLC systems to mitigate the risk of microalgal cell wall damage. Specifically, shallow and narrow TLC systems with high mixing intensities were found to pose a great risk to cell wall integrity. This study provides valuable insights into optimising turbulent mixing in TLC systems, enabling enhanced microalgal cultivation and improved biofuel production. By understanding and managing the impact of turbulent flow on microalgal cell wall integrity, this research contributes to the development of efficient and sustainable TLC systems for microalgae-based applications.