Studying airflow and heat transfer characteristics of a horticultural produce packaging system using a 3-D CFD model. Part II: Effect of package design

Abstract

A 3-D computational fluid dynamics (CFD) model was applied to study the effect of package vent design on airflow and heat transfer during postharvest handling of horticultural products. The effect of vent area, shape, number and position on airflow and heat transfer characteristics was studied. An increase in vent area decreased the total pressure drop and increased the uniformity of airflow and temperature. Total pressure drop was expressed as a function of vent area in the form of a Darcy–Forchheimer equation and the results showed that vent area affected both Darcy and Forchheimer terms. Half and seven eighths cooling times and cooling rate of fruit were expressed as a function of vent area ratio and the results showed that vent number, position and shape mainly affected the uniformity of airflow and cooling. Cooling rate increased with an increase in vent area but the sensitivity of the increase in cooling rate decreased with an increase in vent area. With an increase in vent area up to 7%, there was a reasonable increase in cooling rate; however, further increase in vent area showed a relatively low increase in cooling rate. To optimize package venting, there is a need to combine such airflow and heat transfer studies with analysis of package mechanical integrity.