Numerical Simulation on Water Movement of Humid Porous Food during Freezing Process

• 1、Food School, Shanghai Ocean University, shanghai 201306

Abstract：A numerical simulation was carried to predict the temperature variation and moisture distribution of the cuboid eggplant piece during the forced convection freezing and conduction freezing respectively. The eggplant was considered as porous material in the model. The moisture transportation and change of local temperature of the sample were predicted throughout the freezing process and variable thermo physical properties were adopted in the prediction. The model was validated by experiments and the results of the model showed good agreement with experimental data. The calculation results show that, the water movement towards freezing front during freezing process was apparent. The water movement mainly occurs prior to the freezing, and the lower the freezing temperature and the greater the thickness, the larger the water amount moved. In the forced convection freezing mode, the water amount moved out of the center at the air temperature of -40℃ was 1.32% more than that at the air temperature of -20℃, and was 2.75% larger with the thickness of 42mm than that with the thickness of 24mm under the same other conditions. In the conduction freezing mode, the water amount moved out of the center at the plate temperature of -40℃ was 0.68% more than that at the plate temperature of -20℃, and was 3.47% larger with the thickness of 42mm than that with the thickness of 24mm under the same other conditions. The conduction freezing developed more quick than the forced convection freezing with other factors keep constant.

Keywords： humid porous food freezing mode water movement numerical simulation