What is CFD Modeling?

Computational Fluid Dynamic modeling, or CFD modeling, is the solution of equations for conservation of mass, momentum, energy, and chemical species by computer. The equations typically represent the transport of fuel and air, combustion of the fuel with the air, release and transport of heat, and the formation of pollutants.

To build a CFD model, Steag Energy Services (formerly ESA) engineers will construct a represention of the walls, burners, OFA ports, and exit of a combustion furnace with computer software. The walls will absorb heat, the burners will introduce fuel and air, and the reacted flue gases will leave through the exit. All of these define the boundary conditions for the CFD model.

The interior of the model will be divided into discrete cells, 300,000+ for a typical model. Inside the cells the computer solves the conservation equations using an iterative process requiring several days of number crunching for a typical model. Solution of the equations calculates the values of velocity, temperature, chemical species, and other properties in each cell, that result from the boundary conditions.

From the solution, Steag Energy Services (formerly ESA) engineers create visualizations that graphically represent the distribution of key parameters, such as temperature or NOx production. The visualizations are used to understand the combustion processes occuring and relate them to the parameters of design under consideration, such as number and type of air ports.

Once the influence of the design parameters is well understood, potential improvements can be tested in the CFD model by representing the change and running the model again.

Steag Energy Services (formerly ESA) engineers have spent more than a decade refining the CFD modeling software to accurately and efficiently represent the detailed physical processes involved in combustion.