Abstract
Lean premixed combustion is an effective strategy to reduce harmful emissions; however, flame control remains challenging in industrial combustion systems for stable heat and power generation. While several experimental works have been done in the past, however, some dangerous phenomena are hard to capture experimentally, such as flashback and blow-off scenes due to inherent experimental shortcomings, this is where Computational Fluid dynamics (CFD) studies are crucial to provide deeper insights.
The work proposed in this numerical study presents the CFD analysis of a premixed turbulent flame established in an experimental combustion chamber fueled by producer gas or syngas with composition 1.90% CH4, 18.50% H2, 15 8.85% CO2, 22.20% CO, 7.40% H2O, and 41.15% N2 obtained from woody waste gasification. For the analysis, ANSYS fluent 2024 R1 code is utilized, and the FFCM-2 kinetic model-based CHEMKIN mechanism to account for kinetic, thermodynamic, and transport properties is incorporated to generate a premixed laminar flamelet by the Flamelet Generated Manifold (FGM) approach at different equivalence ratios to store the flame structures in the look-up tables. The effects of the equivalence ratio on generated flamelets are described in the context of parametrized variables, i.e., mixture fraction Z and progress variable Yc. The results obtained from Flamelet-based combustion modeling coupled with the RANS solver are compared against the experimental results, such as flame temperature distribution, and flame topologies measured by IR (Infrared) thermal camera at various thermal loads 24 kW, 10 kW, and equivalence ratios 0.85, 0.43. Moreover, the OH radicals along the flue gas emissions (NOx) are also observed.
Finally, the syngas flame results are visualized and analyzed quantitatively. The discrepancies between numerical and experimental results are discussed, as well as the flame control strategy is more critically examined for efficient flame stabilization at various operating points. Overall, this study aims to contribute to developing efficient lean combustion techniques for clean heat generation.