Numerical Simulations of Highly Preheated Air Combustion in an Industrial Furnace

The numerical simulations of reactive turbulent flows and heat transfer in an industrial slab reheat furnace in which the combustion air is highly preheated have been carried out. The influence of the ratio of the air and fuel injection velocities on the NO x production rate in the furnace has also been studied numerically. A moment closure method with the assumed β probability density function (PDF) for mixture fraction was used in the present work to model the turbulent non-premixed combustion process in the furnace. The combustion model was based on the assumption of instantaneous full chemical equilibrium. The turbulence was modeled by the standard k-e model with a wall function The numerical simulations have provided complete information on the flow, heat, and mass transfer in the furnace. The results also indicate that a low NO, emission and high heating efficiency can be achieved in the slab reheat furnace by using low NO x regenerative burners. It is found that the air/ fuel injection velocity ratio has a strong influence on the NO, production rate in the furnace.

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