Numerical Simulation of Heat Transfer and Fluid Flow at Different Stacking Modes in a Refrigerated Room: Application of Pyramidal Stacking Modes

Abstract

By means of the porous media theory, computational fluid dynamic models of heat transfer and fluid flow at different pack stacking modes in a refrigerated room are elaborated. A practical case is simulated, where brick-shaped packs with aquatic products, partially frozen to 261.15 K, are loaded in the room to complete the freezing process down to 255.15 K, followed by long-term frozen food storage at the latter standard temperature. The best freezing completion effect (defined as the maximum reduction of the highest product temperature during a certain residence time) is achieved by using the pyramidal stacking mode whose upper package is in the center of four lower packages (UPF-PSM) with two piles. The highest temperature of aquatic products at a two-pile-UPF-PSM can be reduced from 261.15 to 255.60 K for a residence time of 24 h. Within the same time, the product temperature becomes most uniform at a UPF-PSM. Simultaneously, the best uniformity of flow distribution and highest efficiency of air circulation in a refrigerated room are obtained by using the neat stacking mode (NSM) during the long-term frozen storage. Furthermore, a comprehensive stacking mode is proposed (using UPF-PSM for freezing completion and NSM for long-term frozen storage), which enhances both the freezing completion effect and the efficiency of air circulation in the studied refrigerated room.