Model based study of the performance of a spray application system in cold storage rooms

摘要

There is an interest in the application of chemical and biocontrol treatments after harvest in the cool room, instead of the commonly used fungicide treatment method by spraying of fruits on the orchard trees and drenching. In this study, a computational fluid dynamics (CFD) model of spray application in cool rooms was used to analyse the suitability of spray systems for postharvest treatments of fruits that are stacked in bins. A two-phase flow model, which consists of one disperse phase (spray droplets) and one continuous phase (air), was used. The model was compared to experimental results of deposition in a loaded cold storage room. The model was applied to study the effect of nozzle characteristics, nozzle position and stacking pattern. The study showed that the deposition of spray droplets containing biological control organism inside a fully loaded room was far from uniform. Most of the droplets were deposited on the outer surfaces of the stack with limited dispersion in the interior of thestack. The model was applied to develop a better spraying procedure and recommend a spraying system that works at single bin level, uses forced airflow to deposit droplets more uniformly inside the bin.