CFD MODELLING OF FUNGICIDE FOGGING SYSTEM FOR POSTHARVEST STORAGE OF FRUIT

摘要

The use of thermonebulisation fogging systems for postharvest fungicide treatments of fruits is a recent development. A three-dimensional computational fluid dynamics (CFD) model was developed and validated to investigate the distribution of fungicide particles inside a cold storage room of 4,75m deep, 4.2m wide and 4.0m high, and loaded with apple fruit in wooden bins. The modelling was based on an Eulerean-Lagrangian multiphase flow model. The model took into account dispersion of the particles due to turbulent airflow. The particle diameter distribution at the exit of thermonebuliser, and the velocity and temperature of the nebulising air were measured and used as an input to the model. The fruit loaded in vented bins was considered as a porous medium. To determine pressure loss coefficients to the three orthogonal directions a multiscale approach was followed. The effect of air ventilation rate and ventilation interval on deposition of fungicide was investigated. The highest fungicide deposition was observed during fogging without ventilation while the lowest deposition corresponded to fogging with the highest ventilation rate (6800m~3 h~(-1)). Good agreement was found between measured and predicted results of deposition of fungicide particles.