Determining the optimal shaking rate of a reciprocal agitation sterilization system for liquid foods: A computational approach with experimental validation

摘要

A new canning process where a reciprocating agitation is carried out in horizontally oriented containers has been recently demonstrated to reduce processing times and enable energy savings with less degradation in the quality of processed food products. Reciprocal agitation by imposing additional forces enhances convective mixing with increased production efficiency. The reciprocal agitation uses the horizontal acceleration in addition to gravity and sum of these forces lead to a considerable increase in the heat transfer rates. In the literature, there have been experimental approaches to evaluate heat transfer enhancement. However, due to the balance among these forces, there might be an optimum reciprocal agitation rate for the increased heat transfer depending upon the physical properties of the liquid processed. Therefore, the objectives of this study were to determine the optimum agitation rates by developing a computational model for heat transfer. For this purpose, a multi-phase model simulation was performed using a finite volume method based on discretization of governing flow equations for liquid and gas phase in a non-inertial reference frame of moving mesh. Experimental studies for model validation were carried out in a reciprocally agitated retort using 98.2 mm x 115 mm cans containing distilled water with 2% headspace as a model case. The model results were in agreement with the experimental data, and the optimum reciprocal agitation rate was determined. The results of this study are to be used to optimize the process with respect to improve the health-promoting compounds of processed foods. (C) 2016 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.