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Engineers at Astec Industries, a leading manufacturer of hot mix asphalt plants, needed to develop a new burner design quickly to accommodate a change in business strategy. Using the traditional build and test method, it would take six to 12 months to get the new burner to market, which would have put a crimp in the company's plans.

Instead, engineers used computer simulation to reduce the time needed to develop a new aggregate drying burner designed for use in asphalt plants to only 32 days. The burner needed to meet stringent requirements for highly efficient combustion and low emissions of NOx, CO and noise, yet there was barely time to build a single prototype.

The design team used computational fluid dynamics (CFD) to evaluate a large number of virtual prototypes and iterate to an optimized design. The most important concern was determining the best way to inject the fuel in order to obtain an ideal gas mixture.

CFD saved a huge amount of time by making it possible to visualize the flow and chemical concentrations throughout the early design iterations, providing far more information than could ever have been obtained from physical experiments. Within two weeks, the design team produced a credible working prototype, and within a month, the team optimized it to improve performance and meet the most stringent NOx and CO regulations. To date, 36 of these burners have been produced and they have delivered excellent performance for customers.

Astec Inc. manufactures a line of hot-mix asphalt plants and soil purification and environmental remediation equipment. The burner described here is used in an aggregate dryer used to remove moisture from rock so it will bind to cement to form asphalt. Astec previously purchased burners, but recently made the decision to design and build its own.