Many companies in the baking industry have come to Agriculture and Agri-Food Canada’s Food Research and Development Centre (FRDC) in Saint-Hyacinthe, Quèbec, Canada, for help in understanding what happens inside a baking oven. While it is not difficult to measure temperatures inside the oven, it is time-consuming and expensive to experiment with many different oven configurations to provide just the right temperature profile for a given product.
The FRDC has overcome this problem by developing a virtual oven using computational fluid dynamics (CFD) to model the distribution of temperature and air velocity, the main factors affecting baking product quality, inside the oven. The new virtual oven makes it possible for food processing companies to quickly evaluate many oven designs to achieve the right cooking properties for the best products.
FRDC sponsors about 20 research teams that carry out joint research with the food industry. FRDC researchers offer high-caliber scientific support for research into bio-ingredients, dairy products, meat products, fruits and vegetables, bakery products, packaging and preservation technologies, fermentation, quality and traceability of foodstuffs, and food engineering.
The ISO-9001:2000 Industrial Program helps the Canadian food industry enhance its competitiveness by increasing, through research, the understanding of food systems and by fostering the development and transfer of new technologies and knowledge. Some 900 companies have carried out more than 1,600 research projects at the FRDC since 1987.
Challenges of Baking Equipment Design
The baking oven project was designed to address problems faced by smaller food processors in optimizing the design of baking equipment. These companies want to produce a product with just the right amount of volume expansion. They are concerned about the effects of the baking process on quality, color, texture, and other food properties.
Typically, these companies perform physical experiments in a small research oven in order to determine the conditions required to bake a product with exactly the right properties. The challenge then becomes reproducing these conditions throughout the interior of a much larger industrial oven.
The complexity of the physics and geometries involved makes it impossible in most practical designs to predict performance using conventional engineering calculations. As a result, the traditional approach to oven design involves creating an initial concept design based on engineering judgment and experience, building and testing a prototype, and then—based on the results—reconfiguring the design and repeating the entire process again and again until an acceptable design is achieved. Unfortunately, experiments such as these are usually quite expensive and time-consuming.
Design Optimization Impossible
Relying completely on experiments is not practical because an oven is normally required to meet production demands, and taking it out of service to perform experiments is expensive. And modifications to the oven may be required, and these add to the costs as well as to the downtime.
Indeed, the time needed to perform all of the experiments required to achieve the right conditions may delay the launch of a new product, sacrificing revenues to competitors. Moreover, cost and time constraints typically make it impossible to optimize a design. Instead, engineers face budget constraints and product introduction targets and often must settle for the first design good enough to meet the product specifications.
CFD can overcome these problems by a virtual oven that can perform a range of experiments by changing its geometry or process conditions. For any oven design engineers can imagine, CFD can compute detailed predictions of flow velocity and temperature for almost any piece of process equipment. Once created and validated, these virtual prototypes are used to investigate multiple design configurations, optimize manufacturing process parameters, and conduct safety studies. By making it possible to investigate more alternatives in less time and at lower cost, flow modeling can help bring better products to market while lowering development costs.
A 3-D, CFD Stand-Alone Virtual Oven
To make it easier and less expensive for smaller baking companies to take advantage of this technology, the FRDC recently developed a three-dimensional CFD stand-alone model of a small baking oven. The objective of the study was to investigate the distribution of temperature and the velocity of the air movement throughout the oven and to compare the simulation predictions with experimental results.