Numerical simulation of freezing time of shelled shrimps in an air blast freezer and experimental verification

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.