In bread-making, the baking process is one of the key steps to produce the final product quality attributes including texture, color and flavor, as a result of several thermal reactions such as non-enzymatic browning reaction, starch gelatinisation and protein denaturation. These thermal reactions are dominated by heat and mass transfer mechanisms inside an oven chamber as well as inside the dough pieces. In this study, an industrial baking process was divided into 4 zones. Experiments were conducted, and mathematical models were developed to account for the heat and mass contribution as well as their consequent impacts on the product qualities. Monitoring systems were developed and installed inside an industrial oven to evaluate oven performance, including temperature profile and airflow pattern. Many other tests and experiments were conducted and results given in some detail. To deal with the complexity of a continuous baking process, a three dimensional transient-state CFD model with moving grids was established to account for the effect of oven load on heat transfer in the oven chamber. The dynamic response of the travelling tin temperature profiles could be predicted in accordance with a change in the oven load. The modelled tin temperature profiles showed a good agreement with the measured tin temperature profiles from the actual industrial baking process. Finally, the three-dimensional CFD model could provide guidance in manipulating the oven condition to achieve the optimum temperature profile in the industrial travelling-tray baking oven. / Doctor of Philosophy (PhD)

Στην παρούσα εργασία θα προσπαθήσουμε να μελετήσουμε τη διαδικασία παραγωγής κεραμοποιίας μεγάλης κλίμακας. Η προσπάθεια αυτή ξεκινά με την ιστορική αναδρομή στην κεραμοποιία και την περιγραφή μιας σύγχρονης μονάδας κεραμοποιίας. Ακολούθως, εξετάζονται οι μέθοδοι με τις οποίες γίνεται η μεταφορά θερμότητας σε επιφάνειες και όγκους. Τέλος, καταλήγουμε στις εξισώσεις που διέπουν τη μεταφορά θερμότητας και στο τελευταίο κεφάλαιο προσπαθούμε να εφαρμόσουμε τις εξισώσεις αυτές σε μια πραγματική μονάδα παραγωγής κεραμοποιίας μεγάλης κλίμακας. / In this work we try to study the process of large-scale ceramic production. This effort begins with the historical background in ceramics and description of a modern ceramics . Next, we will consider the methods by which heat is transferred to surfaces and volumes. Finally , we come to the equations describing the heat transfer and in the last chapter we try to implement these equations in a real plant ceramics.