Fluid dynamics and heat transfer in cold water thawing

Cold water thawing method using running water is most popular when frozen food is required to thaw within a short period of time. Although cold water thawing has long been used commonly in food processing, catering, as well as household cooking, most users do not fully understand the thawing mechanisms and behaviors, leading to poor time control, excessive consumption of water, and unnecessary waste water discharge. In this investigation, numerical modeling and experimental validation were conducted to study the important fluid dynamics and heat transfer in cold water thawing. Computational fluid dynamics (CFD) modeling was employed to analyze the water flow and convective heat transfer on the food surface. Inside the food body, the heat transfer by conduction with a moving phase-change interface was determined by finite difference (FD) method. A parametric study revealed the effects of the flow rate and temperature of the water inlet on the thawing process performance. It was found that the water flow rate could be much less than what commonly used to obtain virtually the same thawing performance. Finally, proper equipment design, control, and operation were recommended to achieve high thawing rate and efficient use of water.