Exploring Flame Characteristics of CH4/CO2/Ammonia/Air Mixtures under Elevated Conditions: An Interferometry-Based Investigation

Document Type : Research Article

Authors

1 Faculty of Mechanical Engineering, University of Kashan, Kashan, Iran

2 School of Mechanical Engineering, College of Engineering, University of Tehran, Tehran, Iran

Abstract

Ammonia (NH3) stands out as a leading option for large-scale renewable energy storage and long-distance transportation. By incorporating landfill gas and raising initial reactant temperatures, NH3 reactivity is effectively enhanced in gas turbines and boilers. This study focuses on exploring the laminar flame propagation of NH3/landfill mixtures under elevated conditions. Accurate predictions for LBVs were achieved through numerical simulations employing Ansys Chemkin-Pro, along with the San Diego, Okafor, and GRI-Mech 3.0 mechanisms. Elevating pressure from 1 to 10 bar resulted in a reduction in laminar burning velocity from 16.1 to 6 cm/s, ultimately leading to an increase in adiabatic flame temperature from 2102 to 2143 attributable to changes in combustion equilibrium.

Also, the results underscored the significant influence of ammonia concentration on augmenting laminar burning velocities. In cases with higher laminar burning velocity, the proportion of NH3 added tends towards zero, while in cases with lower laminar burning velocity, the addition ratio of NH3 tends towards one. The addition of ammonia leads to a reduction in the pool of radicals. Put simply, because ammonia has a lower laminar burning velocity (LBV), the overall LBV of the mixture is reduced as the concentration of ammonia in the fuel mixture increases.

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