Numerical simulation of bread baking in a convection oven

The paper reports on a numerical study conducted to simulate the bread baking process in an industrial convection oven. This involves predicting the unsteady multiphase flow and heat and mass transfer fields within the oven while accounting for changes in bread properties and volume. The clean air and combustion gases circulate inside the oven in two separate compartments. In the clean section, the rotational motion of the blower needed to move air around is modeled following a rotating reference frame approach, while the increase in bread volume is accounted for by a dynamic mesh. Moreover, to predict the motion of the grid, a general model for loaf expansion is developed based on the changes in the volume of the bread's water and carbon dioxide content during baking. In addition, the bread is modeled as a porous material and therefore generated solutions account for the loaf porosity, volume expansion, water evaporation and condensation, starch gelatinization, and release of carbon dioxide. The numerical solution is validated by demonstrating, for one bread, that predictions are in good agreement with experimental measurements. Finally, numerical results for the full setup are reported in the form of hydrodynamic and thermal fields in the oven, contour plots of temperature and volume fraction of water and carbon dioxide along cross-sections of the baking chamber and the bread, bread deformation, and transient profiles of average quantities. It is found that generated results are in agreement with work reported in the literature demonstrating that the developed model can be used to optimize the performance of the oven and the bread baking process.