An aeroponic vertical farm lost an entire harvest due to the massive clogging of its micro-injectors. The investigation revealed a mineralized biofilm, the product of an unforeseen chemical reaction between the fertilizer and the polymeric coating of the pipes. This case, beyond an agronomic problem, represents a chemo-mechanical fatigue failure in materials exposed to cyclic stress and localized corrosion.
Multiphysics Modeling with ANSYS Fluent and MATLAB 🧪
To understand the failure, a digital twin of the injector was implemented. In ANSYS Fluent, the two-phase nutrient flow was simulated, coupling a chemical kinetics model for the reaction between the fertilizer (rich in phosphates) and the polymer monomers. Species concentration data were exported to MATLAB, where a multiaxial fatigue analysis was applied. The surface tension induced by biofilm growth and cyclic hydraulic pressure were calculated. The results identified nucleation points on the internal walls of the injector, where the reaction rate exceeded the material's thermal dissipation capacity.
3D Validation and Lessons for Aeroponic System Design 🔬
Experimental validation came through Artec Studio. Failed injectors were scanned to reconstruct their internal geometry and measure the actual thickness of the mineralized biofilm. By overlaying this point cloud with the fatigue map generated in MATLAB, a 97% correlation was confirmed between the areas of highest simulated stress and the areas of actual clogging. This workflow demonstrates that material fatigue simulation is not just for metals; polymers in contact with aggressive fluids require predictive models to avoid catastrophic losses in precision agriculture.
How to model, using CFD, the interaction between the growth of mineralized biofilms and the evolution of polymeric fatigue in aeroponic micro-injectors to predict their catastrophic clogging?
(PS: Material fatigue is like yours after 10 hours of simulation.)