Numerical simulations of chilling and freezing processes applied to bakery products in irregularly 3D geometries

Abstract

Finite element algorithms implemented in numerical codes were developed by the authors for irregular 3D food systems, to simulate: (i) the chilling process considering domains of different thermo-physical properties, and (ii) the freezing operation using a combined enthalpy and Kirchhoff transformation. The specific heat of the food materials were measured using Differential Scanning Calorimetry and the heat transfer coefficients of the low temperature equipments were determined; this information was further used as inputs in the model. The numerical solutions, previously validated with analytical solutions, were compared to experimental time–temperature curves using different bakery products for chilling and freezing. A good agreement between measurements and model predictions were obtained in all cases. In the complex freezing process the application of the enthalpy–Kirchhoff formulation decreased the computational efforts improving the rate of convergence and the execution speed with respect to the commercial softwares. The codes were applied to determine the required time–temperature conditions for food chilling and freezing.