Measured and predicted temperatures in a grain processing building under heat treatment - 2. Mathematical modeling of heat and mass transfer during heat treatment

Abstract

Heat treatment to control pest insects in grain processing facilities is becoming more widely used because the fumigant methyl bromide has generally been phased out due to its atmosphere ozone-depleting characteristics. Models with finite difference method, using realistic boundary conditions, were developed to predict the heat and mass transfer that occurred on a concrete floor, in the presence and absence of grain, inside a heat-treated building. Temperatures measured every 2 min at 0.5 m below the ceiling and 0.05 m above the bare concrete floor and room relative humidity (RH) were used to model temperature and water loss inside wheat and oats. Temperatures on the surface of the concrete floor and in the grain measured every 2 min during the heat treatment were used to verify and validate the developed models. The maximum and minimum residues between the measured and predicted temperatures of the concrete floors under grain were 3.2°C and -2.8°C, respectively. The larger residues were mostly located at the beginning of the heat treatment. After concrete floor temperatures reached 25°C, the residues between the measured and calculated temperatures of concrete floors under grain were less than ±1°C. These residues were also less than the differences between the temperatures measured in different replicates.