Computer-aided design and experimental testing of continuous flow cooling of viscous foods

摘要

Computer-aided studies, comprising computational fluid dynamics and heat transfer models, were used to simulate continuous flow cooling of viscous foods. Initially, model validation studies were conducted, giving a good correlation between simulation results and experimental data on cooling of sweet potato puree. Additional computer-aided studies were performed to compare cooling efficiency of two different flow configurations, with the product flowing within the inner tube and the annulus of a tube-in-tube heat exchanger, respectively. Cooling of sweet potato puree was significantly improved for the annular product flow compared with the other case, resulting in a bulk temperature at the exit of the heat exchanger lower by 124 degrees C. Therefore, the simulation results indicate that annular product flow could potentially improve cooling efficiency by 25% for sweet potato puree, due to the increased heat transfer to the environment.Practical applicationsDuring cooling of viscous foods, such as fruit and vegetable purees, laminar flow, and low thermal conductivity lead to a nonuniform, slow cooling process resulting in degradation of food quality. Improvement and optimization of the cooling process in a tube-in-tube heat exchanger, with an implementation of annular flow for the product, could potentially result in (1) enhancement of cooling efficiency, (2) reduction of cooling-related product quality losses, and (3) improvement of sanitary conditions, by eliminating condensation formation.