摘要
食品冻结时间对速冻食品的质量和速冻过程的能耗有着重要影响。为弥补实验测量耗时耗材局限性大的缺陷,该文采用计算流体力学(CFD),对虾仁在鼓风冻结装置中的冻结过程及冻结时间进行了二维非稳态模拟。实验验证表明模型与实际吻合较好,冻结过程中最大温差1.5℃,冻结时间差异百分比为3.8%。在此基础上,还对可能影响食品冻结时间的多个参数(吹风方式,吹风速度,送风温度)进行了模拟研究,结果表明:相比于单侧送风,上下同时吹风的方式大大提高食品换热系数,从而大幅缩短冻结时间;上吹风速度恒定时,随着下吹风速度增大,冻结速率加快;降低送风温度,冻结时间明显减少,但减少的幅度随着冻结温度的降低而不断减小。
Freezing time has great influence on the quality of foods and energy consumption in the quick-freezing process. In order to compensate the defects of consuming of time and materials and great limitation for test, computational fluid dynamics （CFD） technology is employed for more effectiveness and convenience. In this paper, a two-dimension unsteady mathematical model was established to simulate the heat transfer process of the quick-freezing of shelled fresh shrimps and the freezing time in an air blast freezer by CFD technology. The simulation results fitted experimental data well, for instance, the maximum temperature difference between the experimental data and simulation result was 1.5℃ with the relative error of 3.8%. It showed that the mathematical model and the simulation methods were reliable. After that, several design parameters （air blast way, air velocity and air temperature） which would affect the freezing time were analyzed. Results indicate that two-side air-blast, an increase in air velocity, and a decrease in air temperature reduce the freezing time of foodstuffs. But decrease range reduces with the drop of freezing temperatue.
出处
《农业工程学报》
EI
CAS
CSCD
北大核心
2009年第4期248-252,F0004,共6页
Transactions of the Chinese Society of Agricultural Engineering
基金
上海市科技兴农重点攻关项目(沪农科攻字(2006)第 7-1 字)
上海市重点学科建设项目资助(T1102)
关键词
冻结
鼓风
数值分析
数学模型
计算流体力学
freezing, air blast, numerical analysis, mathematical models, computational fluid dynamics
