Simulation and Analysis of Forced-air Precooling of Apples with Vertical Air Supply

被引：0
作者：
Jin T. [1 ,2 ]
Li B. [1 ,2 ]
Zhu Z. [3 ]
Han S. [3 ]
Wei J. [1 ,2 ]
机构：
[1] Institute of Refrigeration and Cryogenics, Zhejiang University, Hangzhou
[2] Key Laboratory of Refrigeration and Cryogenic Technology of Zhejiang Province, Zhejiang University, Hangzhou
[3] Tianjin Key Laboratory of Refrigeration Technology, Tianjin University of Commerce, Tianjin
来源：
Nongye Jixie Xuebao/Transactions of the Chinese Society for Agricultural Machinery | 2021年 / 52卷 / 09期
关键词：
Apples; Cooling performance; Forced-air precooling; Numerical simulation; Vertical air supply;
D O I：
10.6041/j.issn.1000-1298.2021.09.042
中图分类号：
学科分类号：
摘要：
Forced-air precooling is helpful in preserving the quality of fruits and vegetables. Compared with the traditional horizontal pattern, the vertical forced-air precooling has higher cooling efficiency. Computational fluid dynamics model of vertical forced-air precooling of apples was built to analyze the influence of air-inflow velocity, air-inflow temperature and the ratio of vessel aperture area on the performance of vertical forced-air precooling. It was found that when the air-inflow velocity was increased from 0.5 m/s to 2.5 m/s, the cooling time of apple was decreased from 127 min to 90 min, the main variation of the center of apples was decreased from 0.51℃ to 0.20℃, and the weight loss rate was decreased from 0.007 86% to 0.005 70%. When the air-inflow temperature was increased from 2℃ to 6℃, the cooling time remained unchanged and the finishing temperature was close to the air supply temperature. When the opening area of box was increased from 15% to 30%, the cooling rate was almost unchanged, the pressure drop was decreased from 418 Pa to 86.8 Pa, the mean variation of the center of apples was increased from 0.73℃ to 1.11℃, and the weight loss rate was about 0.006%. Concerned with the actual situation, the optimal pre-cooling air-inflow velocity of vertical forced-air precooling was about 2.0 m/s, which was lower than that of horizontal forced-air precooling. It was advisable to adopt the smaller box opening area to ensure the structural strength if the pressure drop was acceptable. In order to reduce the weight loss rate, air should flow evenly over all apple surfaces to ensure the surface temperatures drop as quickly as possible. By comparing with the experimental data, it was found that the results obtained by the model adopted were basically consistent with the trend of the experimental results, and the maximum temperature difference did not exceed 1.5℃, which can be used to evaluate the performance of precooling with air pressure difference in vertical delivery of apples. © 2021, Chinese Society of Agricultural Machinery. All right reserved.
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页码：369 / 375
页数：6
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