Modelling and Simulation of Heat Transfer in a Industrial Tunnel Oven for Bread Baking

Baking tunnel ovens are the primary thermal processing equipment in industrial bread production, and their design and operational parameters critically determine product quality consistency and energy efficiency. The absence of validated heat transfer models for Nigerian bread formulations and oven geometries represents a gap in the process engineering knowledge base for the domestic baking industry. This study develops and validates a computational fluid dynamics model for heat transfer in a 30-metre tunnel oven at a commercial bakery in Lagos, South West Nigeria. The finite element model incorporates convective heat transfer from hot air flow, infrared radiation from oven deck elements, and conductive heat transfer through the product. Dough formulation thermophysical properties including thermal conductivity, specific heat, and density were measured as functions of temperature and moisture content. The model was validated against experimental temperature profiles measured using thermocouple data loggers inserted into bread loaves at three oven positions. Model predictions of core temperature and surface colour as measured by the Maillard browning index agreed with experimental values within 5 percent and 8 percent respectively. Parametric studies evaluated the effects of oven air velocity, zone temperature profiles, and loading density on crust formation rate, crumb temperature distribution, and specific energy consumption. Optimal zone profiles that reduced energy consumption by 12 percent while maintaining target crust colour were identified. The study contributes to industrial baking process engineering and draws on recent computational fluid dynamics applications in food processing. Keywords: heat transfer, tunnel oven, bread baking, computational fluid dynamics, process modelling