The Effect of Variable Air–Fuel Ratio on Thermal NOx Emissions and Numerical Flow Stability in Rotary Kilns Using Non-Premixed Combustion

One of the quickest ways to influence both the wall temperature and thermal NOx emissions in rotary kilns is to change the air–fuel ratio (AFR). The normalized counterpart of the AFR, the equivalence ratio, is usually associated with premixed flames and studies of its influence on diffusion flames are inconsistent, depending on the application....

Mitigating Thermal NOx by Changing the Secondary Air Injection Channel: A Case Study in the Cement Industry

This work studies how non-premixed turbulent combustion in a rotary kiln depends on the<br/>geometry of the secondary air inlet channel. We target a kiln in which temperatures can reach values above 1800 degrees Kelvin. Monitoring and possible mitigation of the thermal nitric-oxide (NOx) formation is of utmost importance. The performed reactive...

Modelling Turbulent Combustion Coupled with Conjugate Heat Transfer in OpenFOAM

This paper verifies a mathematical model that is developed for the open source CFD-toolbox OpenFOAM, which couples turbulent combustion with conjugate heat transfer. This feature already exists in well-known commercial codes. It permits the prediction of the flame’s characteristics, its emissions, and the consequent heat transfer between...

Non-premixed combustion in rotary kilns using OpenFOAM: the effect of conjugate heat transfer and external radiative heat loss on the reacting flow and the wall

The wish to reduce the environmental footprint and to enhance economic gains of rotary kilns pushes the numerical simulation of combustion to include conjugate heat transfer. In this paper we study the influence of the refractory wall and radiative heat loss to the ambient, on the combustion process of a reference kiln model. Numerical results...