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CFD Simulation of Airflow and Heat Transfer During Forced‐Air Precooling of Apples
Author(s) -
Han Jiawei,
BadÍamelis R.,
Yang Xinting,
Ruizgarcia L.,
Qian Jianping,
Zhao Chunjiang
Publication year - 2017
Publication title -
journal of food process engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.507
H-Index - 45
eISSN - 1745-4530
pISSN - 0145-8876
DOI - 10.1111/jfpe.12390
Subject(s) - airflow , heat transfer , mechanics , forced air , work (physics) , convective heat transfer , forced convection , convection , thermodynamics , environmental science , heat transfer coefficient , meteorology , chemistry , materials science , physics
In this work, we study how different air‐inflow velocities affect the apple‐temperature distribution during forced‐convection cooling of individual apples by simultaneously modeling airflow and heat transfer. In general, an increase in airflow velocity increases the cooling rate and heat transfer fluxes across the apple surface and decreases cooling time. The results show that a reasonable increase in cooling rate is obtained with an increase in airflow velocity to 2.5 m/s; any further increase in airflow velocity simply wastes energy because it leads to a relatively low increase in cooling and heat transfer fluxes across the apple surface. By comparing the temperature simulated with and without accounting for respiratory heat, the maximum temperature difference is ∼0.033 K during cooling. Therefore, respiratory heat has a negligible effect on the temperature variations of fruit. The model was verified by comparing its results with those of experiments. The predicted results are consistent with the measured results. Practical Applications To ensure the quality and safety of horticultural products and extend their storage and shelf life across the entire cold chain, a critical step in the postharvest cold chain is the rapid precooling after harvest to remove field heat. In this work, we investigate how to improve the cooling rate and minimize the cooling time during forced‐convection cooling of apples. In addition, the effect of respiratory heat on temperature variations of fruit is also studied. This research provides not only a more detailed understanding of flow distribution and temperature variations of fruit during cooling, but also a reliable theoretical basis for minimizing unnecessary energy consumption during forced‐convection cooling of produce.