Shear stress computation in a millimeter thin flat panel photobioreactor: Numerical design validated by experiments.

Area of Science:

• Biotechnology
• Photobioreactor Design
• Microalgae Cultivation

Background:

• Flat panel photobioreactors are common for microalgae studies, but limited by low cell density due to light penetration.
• Thinner designs increase shear stress, potentially inhibiting cell growth.

Purpose of the Study:

• To design a novel millimeter-thin flat panel photobioreactor for studying light effects on Chlorella and Scenedesmus.
• To develop and validate a numerical workflow for assessing shear stress in thin photobioreactors.

Main Methods:

• Utilized a numerical workflow for shear stress assessment.
• Validated simulations through 2D preliminary tests, shadowgraphy, and mini bioreactor experiments.
• Calculated shear stress using 1000 Lagrangian tracers and population-level analysis.

Main Results:

• The numerical workflow accurately predicted bubble behavior, nozzle dynamics, and mixing.
• Shear stress intensity was quantified across the photobioreactor.
• Identified the minimal reactor thickness to prevent growth hindrance.

Conclusions:

• A validated numerical method can assess shear stress in millimeter-thin photobioreactors.
• Optimized reactor thickness is crucial for maintaining microalgae growth in thin designs.
• This approach facilitates high-density microalgae cultivation for research.