Investigating the Potential of Different Modeling Setups in Simulating a Flameless Furnace Using Global and Detailed Kinetic Mechanisms

ABSTRACT

Attempts were made to reproduce the laboratory measurements of flameless combustion systems using numerical simulation tools, for different chambers designs. In many cases, a significant discrepancy is reported between the experimental measurements and the numerical results. In this work, we have successfully reproduced the reported experimental results (velocity field, temperature field, and the outlet dry NOx emissions) of the “FOUR” MILD combustion facility (proposed by C. Rottier). An acceptable accuracy was achieved in two reference test cases. A concise discussion is presented on the available literature on the subject of numerical modeling for the flameless combustion mode. The use of two turbulence models was explored (standard k-ε, and modified k-ε), along with two kinetic mechanisms (a global 2-step CH₄ combustion mechanism, and the more detailed KEE-58 mechanism). The commercial ANSYS FLUENT® software was used in these simulations. The results of seven different modeling setups are presented, comparing the predictions of temperature fields, and NO_X emissions. Features such as the onset of premature ignition and the reactants entrainment ratio are also discussed. Our results show that the most accurate model setup employs the following: SKE – KEE-58 – EDC with a reduced volume fraction constant. In regards to reproducing the measurements from the “FOUR” facility, we are not aware of a similar research that runs a concise discussion on the predictions of such broad and different modeling setups.

KEYWORDS:

• Flameless combustion technology
• emissions reduction
• numerical simulation
• industrial furnace

Compliance with Ethical Standards

The authors declare that they have no conflict of interest. This study received no funding.