Due to the significant reduction in water droplet size caused by the strong air-water interaction in the spray nozzle, air-mist spray is one of the promising technologies for achieving high-rate heat transfer. This study numerically analyzed air-mist spray produced by a flat-fan atomizer using three-dimensional computational fluid dynamics simulations, and a multivariable linear regression was used to develop a correlation to predict the heat transfer coefficient using the casting operating conditions such as air-pressure, water flow rate, casting speed, and standoff distance. A four-step simulation approach was used to simulate the air-mist spray cooling capturing the turbulence and mixing of the two fluids in the nozzle, droplet formation, droplet transport and impingement heat transfer. Validations were made on the droplet size and on the VOF-DPM model which were in good agreement with experimental results. A 33% increase in air pressure increases the lumped HTC by 3.09 ± 2.07% depending on the other casting parameters while an 85% increase in water flow rate reduces the lumped HTC by 4.61 ± 2.57%. For casting speed, a 6.5% decrease in casting speed results in a 1.78 ± 1.42% increase in the lumped HTC. The results from this study would provide useful information in the continuous casting operations and optimization.

The use of lead reverberatory furnaces is a common part of the lead recycling process, wherein a solid feed material comprising various lead compounds is directly exposed to combustive and radiative heat sources to melt the feed material and produce lead product. Furnace design decisions ranging from burner inputs to burner placement and furnace shape are difficult to trial without risking costly losses in productivity. The use of modern computational fluid dynamics approaches can allow for more-accurate modeling of the reverberatory furnace process. A steady state simulation of the reverberatory furnace has been created for this purpose. The direct modeling of the melting and smelting reactions is bypassed as this effort would be very computationally expensive and require detailed kinetic data, a large portion of which is unknown. However, as these reactions are largely endothermic, their influence on the overall temperature profile of the furnace cannot be ignored and is critical to both validation and usefulness of the model. To this end, a multi-variable artificial heat sink boundary condition has been placed on several key boundary surfaces within the furnace for the purpose of representing the heat consumption caused by the melting and smelting reactions. This boundary condition is tuned through parameter adjustment in the base study until the temperature profile matches sample data taken from furnace operation measurements.

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