SIMULATING HEAT ANDMASS TRANSFER OVER A SINGLE LEAF AND CORRELATING WITH DISCRETE GREEN'S FUNCTIONS

Ventilation plays a crucial role in optimizing microclimates within vertical farms, where plant leaves continuously exchange heat and water vapor with their surroundings. This study develops a computational fluid dynamics (CFD) model that couples heat and mass transfer at the leaf level. A numerical methodology is implemented to calculate the local leaf temperatures based on energy balance equations, accounting for transpiration-driven cooling. To verify the CFD methodology, discrete Green's functions (DGFs)-a proven analytical method for convective heat transfer-are extended to also model mass transfer, allowing for a coupled heat and moisture transport analysis. The verification process first compared CFD and DGF results in a 2D flat plate case, where relative errors remained below 2%. The approach was then extended to a 3D leaf geometry, confirming strong agreement, with errors staying under 5%. To assess model robustness, 96 simulations were performed, systematically varying airflow velocity, radiation intensity, and stomatal resistance. The results illustrate key interactions between environmental conditions and leaf transpiration, such as counterintuitive reductions in transpiration under increased velocity when radiation is present. This validated CFD framework provides a reliable tool for modeling plant microclimates and optimizing climate control in greenhouses and vertical farms. Future research will extend this approach to simulate full plant architectures and improve environmental regulation strategies in controlled agriculture.