A NUMERICAL PREDICTION MODEL FOR FOOD FREEZING USING FINITE-ELEMENT METHOD

The rate of freezing is one of the most important factors in designing an efficient freezing process for foods in order to achieve good product quality and to avoid excessive energy consumption. Significant improvements have been achieved in the area of freezing process simulation, however, the phenomena of phase-change, the influence of product thermal properties, the importance of product geometry and the effect of freezing environment on the freezing rate are not fully understood.;The objective of this investigation was to develop a numerical simulation model using the finite element method to predict freezing rate in anomalous food product geometries while accounting for the non-linear temperature dependent product properties and various boundary conditions. To verify the model, experimental tests were conducted for elliptical and trapezoidal product shapes using ground beef as the food product. The experiments were conducted in a wind tunnel placed in a low temperature room and temperature measurement was recorded for 24 node locations within the critical cross-section of the product during the freezing process.;The finite element computer simulation used to predict the food product freezing rate of anomalous shape has been developed and verified by experimental data. The results illustrate the capability of the simulation model to incorporate various boundary conditions and various product geometries. Closer approximation to the experimental data was obtained by using the prediction incorporating a boundary condition with the surface heat transfer coefficient varying as a function of location. More efficient freezing times are predicted by utilizing an approach based on area average enthalpy as compared to the conventional method based on the slowest freezing point location. Time steps in the range from one to three minutes do not influence the stability of the finite element scheme. While geometric size has significant influence on the rate of freezing, the influence on initial product temperature in the range from 14.0 to 22.0(DEGREES)C interval is negligible.