STUDY ON THE FORCED-AIR PRECOOLING PROCESS OF TORISPHERECIAL FRUITS AND VEGETABLES IN COOLING BED

摘要

A mathematical model is supposed to describe the heat and mass transfer in the forced-air precooling for torispherecial fruits and vegetables. The model is solved by finite volume method. The critical parameters in the precooling such as velocity, humidity ratio，layers of torispherecial fruits and vegetables, and respiration heat of the torispherecial fruits and vegetables are discussed, respectively. Velocity of 1.5m/s is one of the best operation parameters. Precooling time increases with void ratio in cold air and layers of torispherecial fruits and vegetables. The heat of respiration has little effect on the precooling process. The temperature field in the fruits and vegetables at any times in the precooling, the temperature of the different layers, and the temperature distribution of the cold air along the velocity direction are described. Calculation results are proved by the experiments. It can be concluded that the model gives better predictive results for practical precooling.