Simulation-Based Analysis of the Effect of New Immersion Freezing Equipment on the Freezing Speed

Abstract

Modeling software was used to improve the efficiency of existing immersion freezing equipment. The concept of adding a rotating hopper device was proposed to make pork rotate with the rotating hopper in a flowing refrigerant carrier to achieve the effect of shortening the freezing time. In order to make up for the shortcomings of time-consuming processes and the limited information obtained from the measurement of the central temperature of pork, this paper establishes a mathematical model of the pre-freezing process using computational fluid dynamics (CFD) software to simulate the three-dimensional unsteady state of the pork. The simulation results show that when the rotating hopper is stationary, the refrigerant circulation flow shortens the freezing speed by 490 s compared to the freezing speed in the stationary state of the refrigerant carrier, and the freezing time efficiency is improved by 9.5%. When the refrigerant carrier flow rate v = 0 m/s and when the hopper speed r = 2 rad/s, the central temperature of pork drops rapidly from 26 °C to −15 °C in 0~1250 s, the decline leveled off at 1250–2310 s, and finally dropped to −18 °C, requiring a total of 5410 s. The freezing time of the immersion and freezing equipment was reduced by 2830 s after the addition of the rotating device, improving efficiency by nearly 55%. When the rotation speed r is increased from 2 rad/s to 4 rad/s, the freezing time is shortened by 1290 s and the freezing efficiency is increased by nearly 53%. The addition of the rotating device will make the pork freezing effect more uniform.